Qore Programming Language Reference Manual  0.8.11.1
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Qore::SQL::Datasource Class Reference

This class provides the Qore interface to databases. More...

Inheritance diagram for Qore::SQL::Datasource:

Public Member Functions

nothing beginTransaction ()
 Manually grabs the transaction lock. More...
 
nothing clearEventQueue ()
 Clears the queue object for DBI events on the datasource. More...
 
nothing close ()
 Closes the connection to the database; if any actions are in progress on the database, the close call will block until the actions complete. If any errors are encountered, an exception is raised. More...
 
nothing commit ()
 Commits the current transaction and releases the transaction lock. More...
 
 constructor (string driver, *string user, *string pass, *string db, *string encoding, *string host, *softint port, *hash options, *Qore::Thread::Queue queue, any arg)
 Creates the Datasource object; attempts to load a DBI driver if the driver is not already present in Qore. More...
 
 constructor (string desc, *Qore::Thread::Queue queue, any arg)
 Creates a Datasource object from a single string giving all parameters that can be parsed by parse_datasource() More...
 
 constructor (hash opts, *Qore::Thread::Queue queue, any arg)
 Creates a Datasource object from a hash argument giving parameters for the constructor. More...
 
 copy ()
 Creates a new Datasource object with the same driver as the original and copies of all the connection parameters. More...
 
bool currentThreadInTransaction ()
 Returns True if the current thread is in a transaction (i.e. holds the transaction lock), False if not. More...
 
*hash describe (string sql,...)
 Executes an SQL select statement on the server and returns a description of the result set as a hash. More...
 
 destructor ()
 Closes the datasource if it's open (if any operations are in progress, will block until the operations complete) and destroys the object. More...
 
any exec (string sql,...)
 Grabs the transaction lock (if autocommit is disabled) and executes an SQL command on the server and returns either the integer row count (for example, for updates, inserts, and deletes) or the data retrieved (for example, if a stored procedure is executed that returns values). More...
 
any execRaw (string sql)
 Grabs the transaction lock (if autocommit is disabled) and executes an SQL command on the server and returns either the row count (for example, for updates and inserts) or the data retrieved (for example, if a stored procedure is executed that returns values) More...
 
bool getAutoCommit ()
 Returns the autocommit status for the object. More...
 
int getCapabilities ()
 Returns an integer bitfield of DBI driver capabilities. More...
 
list getCapabilityList ()
 Returns a list of strings giving the capabilities of the current DBI driver. More...
 
any getClientVersion ()
 Retrieves the driver-specific client library version information; this method may not be implemented for all drivers. More...
 
hash getConfigHash ()
 Returns a datasource hash describing the configuration of the current object. More...
 
string getConfigString ()
 Returns a string giving the configuration of the current object in a format that can be parsed by parse_datasource() More...
 
string getDBCharset ()
 Retrieves the database-specific charset set encoding for the current connection. More...
 
string getDBEncoding ()
 Retrieves the database-specific charset set encoding for the current connection. More...
 
*string getDBName ()
 Returns the database name parameter as a string or NOTHING if none is set. More...
 
string getDriverName ()
 Returns the name of the driver used for the object. More...
 
*string getHostName ()
 Returns the hostname parameter as a string or NOTHING if none is set. More...
 
string getOSCharset ()
 Returns the Qore character encoding name for the current connection as a string or "(unknown)" if none is set. More...
 
*string getOSEncoding ()
 Returns the Qore character encoding name for the current connection as a string or NOTHING if none is set. More...
 
any getOption (string opt)
 Returns the current value for the given option. More...
 
hash getOptionHash ()
 returns the valid options for the driver associated with the Datasource with descriptions and current values for the current Datasource object More...
 
*string getPassword ()
 Returns the password parameter as a string or NOTHING if none is set. More...
 
*int getPort ()
 Gets the port number that will be used for the next connection to the server. More...
 
any getServerVersion ()
 Returns the driver-specific server version data for the current connection. More...
 
int getTransactionLockTimeout ()
 Retrieves the transaction lock timeout value as an integer in milliseconds. More...
 
*string getUserName ()
 Returns the username parameter as a string or NOTHING if none is set. More...
 
bool inTransaction ()
 Returns True if a transaction is currently in progress, False if not. More...
 
nothing open ()
 Opens a connection to the datasouce, using the connection parameters already set; an exception is thrown if any errors occur. More...
 
nothing reset ()
 Closes and reopens the Datasource. More...
 
nothing rollback ()
 Rolls the current transaction back and releases the transaction lock. More...
 
any select (string sql,...)
 Executes an SQL select statement on the server and returns the result as a hash (column names) of lists (column values per row) More...
 
*hash selectRow (string sql,...)
 Executes an SQL select statement on the server and returns the first row as a hash (the column values) More...
 
any selectRows (string sql,...)
 Executes an SQL select statement on the server and returns the result as a list (rows) of hashes (the column values) More...
 
nothing setAutoCommit (bool ac=True)
 Turns autocommit on or off for this object. More...
 
nothing setDBCharset (string encoding)
 Sets the database-specific character encoding name for the next connection to the server. More...
 
nothing setDBEncoding (string encoding)
 Sets the database-specific character encoding name for the next connection to the server. More...
 
nothing setDBName (string db)
 Sets the database name parameter for the time a connection to the server is established. More...
 
nothing setEventQueue (Qore::Thread::Queue queue, any arg)
 Sets a queue object for DBI events on the datasource. More...
 
nothing setHostName (string host)
 Sets the hostname to use for the next connection to the server. More...
 
 setOption (string opt, any val)
 sets an option for the datasource More...
 
nothing setPassword (string pass)
 Sets the password parameter for the time a connection to the server is established. More...
 
nothing setPort (softint port=0)
 Sets the port number to use for the connection. More...
 
nothing setTransactionLockTimeout (timeout timeout_ms=0)
 Sets the transaction lock timeout value in milliseconds; set to 0 for no timeout. More...
 
nothing setUserName (string user)
 Sets the username parameter for the time a connection to the server is established. More...
 
int transactionTid ()
 Returns the TID of the thread holding the transaction lock or -1 if it's not currently held. More...
 
any vexec (string sql, *softlist vargs)
 Grabs the transaction lock (if autocommit is disabled) and executes SQL code on the DB connection, taking a list for all bind arguments. More...
 
any vselect (string sql, *softlist vargs)
 Executes a select statement on the server and returns the results in a hash (column names) of lists (column values per row), taking a list for all bind arguments. More...
 
*hash vselectRow (string sql, *softlist vargs)
 Executes a select statement on the server and returns the first row as a hash (column names and values), taking a list for all bind arguments. More...
 
any vselectRows (string sql, *softlist vargs)
 Executes a select statement on the server and returns the results in a list (rows) of hashes (column names and values), taking a list for all bind arguments. More...
 
- Public Member Functions inherited from Qore::SQL::AbstractDatasource
bool currentThreadInTransaction ()
 Should return True if the current thread is in a transaction with this object, must be re-implemented in subclasses to provide the desired functionality. More...
 

Detailed Description

This class provides the Qore interface to databases.

Restrictions:
Qore::PO_NO_DATABASE

This class provides the main direct interface to DBI drivers (along with the SQLStatement and DatasourcePool classes).

The Datasource class will attempt to load any DBI driver that is not currently loaded in the constructor. For connection pooling support, see the DatasourcePool class.

Datasource objects will implicitly call Datasource::open() if no connection has yet been established and a method is called requiring a connection to the database server. Therefore any method that requires communication with the database server can also throw any exception that the open method can throw.

Most Qore DBI drivers allow "select" queries to be executed through the Datasource::exec() method, and allow SQL commands (procedure calls, etc) to be executed through the Datasource::select() method, and some DBI drivers do not (depends on the underlying DB API). At any rate, the transaction lock is set when auto-commit is disabled and when the Datasource::exec() or Datasource::beginTransaction() methods are executed as documented above. Therefore executing a transaction relevant command through the Datasource::select() method while auto-commit mode is disabled and a transaction has not yet started will not result in the transaction lock being allocated to the current thread and therefore could cause transaction errors when sharing the Datasource object between multiple threads.

Only databases with an existing Qore DBI driver can be accessed through the Datasource class.

All Qore DBI drivers set new connections to use transaction isolation level "read committed".

The Datasource class provides high-level, per-connection locking on requests at a level above the DBI drivers to ensure that the communication between clients and servers is properly serialized.

Datasource objects also have a default character encoding; all requests to the server will be made in this encoding, and all responses will be returned in the given encoding. If no encoding is specifically given to the Datasource object, the Datasource object will use the Default Character Encoding.

Datasource Binding By Value and By Placeholder

All Datasource methods accepting SQL strings to execute understand a special syntax used in the query string to bind Qore data by value and to specify placeholders for output variables (for example, when executing a stored procedure or database function). Placeholder binding is DBI driver specific, but binding by value is supported with the same syntax in all drivers. Additionally, the %d numeric specifier is supported equally in all Qore DBI drivers.

Datasource Format Specifiers

Format Specification Description
%d If any value other than NOTHING or NULL is given, then the value is converted to an integer and this value is substituted in the string at this position; if the value is NOTHING or NULL, then a literal "null" is substituted instead.
%s The argument is converted to a string and the string is inserted literally without any conversion or escape sequences in the string; this is useful for table or schema prefixes, etc
%v The argument is bound by value according to the DBI driver's implementation.

To bind Qore data values directly in a binary format in an SQL command, use %v in the command string, and include the value as an argument after the string. Binding by value allows the DBI driver to take care of formatting the data properly for use in the query with the database server. When binding by value, strings do not need to be quoted, date/time values do not need special formatting, binary objects (with BLOB columns, for example) can be used directly in queries, etc.

Here is an example:

my int $rows = $db.exec("insert into table (varchar_col, timestamp_col, blob_col, numeric_col) values (%v, %v, %v, %d)", $string, now(), $binary, 100);

When using dynamic SQL, to insert a numeric value or a literal "null" in a query, use %d in the command string, and include the value as an argument after the string. If the value is NOTHING or NULL, a literal "null" will be written to the string; otherwise the argument is converted to an arbitrary-precision number or integer value if necessary and written to the string. This is useful for working with DECIMAL (NUMERIC, NUMBER) types in a database-independent way; for example PostgreSQL servers do not do type conversions to DECIMAL types when a string, integer, or float is bound by value, therefore to ensure that integral decimal values can be used in a database-independent way (with "null" substitution when no value is bound), a valid approach is to use the %d code in the command string instead of %v. However please note that %v is normally preferred to keep the server-side statement cache a manageable size, in the previous example using the int(), float(), or number() functions to convert string values before binding with %v may be better.

For binding placeholders for output variables, write a unique name in the string and prefix it with a colon (ex: ":code"). In this case the method will return a hash of the output variables using the placeholder names as keys, but without the colon prefix. By default, a string type will be bound to the position. To bind other variable types to placeholder positions, include the type constant (see SQL Constants) as an argument after the command string. For BLOBs, use Binary, for CLOBs, use the string "clob" (constants will be provided in a future release). Not all DBI drivers require placeholder buffer specifications; see the documentation for the DBI driver in question for more information and examples regarding placeholder buffer specifications.

Datasource Transaction Locks

Datasource objects have an internal transaction lock which will be grabbed when the Datasource::exec(), Datasource::vexec() Datasource::execRaw(), or Datasource::beginTransaction() methods are executed and autocommit is not enabled. This enables a single datasource to be safely used for transaction management by several threads simultaneously. Note that an exception in a Datasource method that would acquire the lock (such as the Datasource::exec() method) when it's not already held, will have the effect that the transaction lock is not acquired.

Any thread attempting to do transaction-relevant actions on a Datasource with auto-commit disabled while a transaction is in progress by another thread will block until the thread currently executing a transaction executes the Datasource::commit() or Datasource::rollback() methods (or the Datasource is deleted, reset, or closed, in which case the lock is released and an exception is raised as well).

There is a timeout associated with the transaction lock; if a thread waits for the transaction lock for more than the timeout period, then an exception will be raised in the waiting thread. The timeout value can be read and changed with the Datasource::getTransactionLockTimeout() and Datasource::setTransactionLockTimeout() methods, respectively. The default transaction lock timeout value is 120 seconds.

Note that the SQLStatement class also grabs the transaction lock when executing if it is created using a Datasource object in the constructor; for more information see the SQLStatement class.

Note
This class is not available with the PO_NO_DATABASE parse option
See also
SqlUtil for a high level database-independent API

Member Function Documentation

nothing Qore::SQL::Datasource::beginTransaction ( )
virtual

Manually grabs the transaction lock.

This method should be called when the Datasource object will be shared between more than 1 thread, and a transaction will be started with a Datasource::select() method or the like.

This method does not make any communication with the server to start a transaction; it only allocates the transaction lock to the current thread in Qore.

It is an error to call this method when autocommit is enabled for the Datasource.

Example:
$db.beginTransaction();
Exceptions
AUTOCOMMIT-ERRORCannot start a transaction when autocommit is enabled
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock

Implements Qore::SQL::AbstractDatasource.

nothing Qore::SQL::Datasource::clearEventQueue ( )

Clears the queue object for DBI events on the datasource.

Since
Qore 0.8.9
nothing Qore::SQL::Datasource::close ( )

Closes the connection to the database; if any actions are in progress on the database, the close call will block until the actions complete. If any errors are encountered, an exception is raised.

Example:
$db.close();
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions
nothing Qore::SQL::Datasource::commit ( )
virtual

Commits the current transaction and releases the transaction lock.

Example:
$db.commit();
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

Qore::SQL::Datasource::constructor ( string  driver,
*string  user,
*string  pass,
*string  db,
*string  encoding,
*string  host,
*softint  port,
*hash  options,
*Qore::Thread::Queue  queue,
any  arg 
)

Creates the Datasource object; attempts to load a DBI driver if the driver is not already present in Qore.

Parameters
driverThe name of the DBI driver for the Datasource. See SQL Constants for builtin constants for DBI drivers shipped with Qore, or see the DBI driver documentation to use an add-on driver (this string should be the name of the driver to be loaded)
userThe user name for the new connection. Also see Datasource::setUserName() for a method that allows this parameter to be set after the constructor.
passThe password for the new connection. Also see Datasource::setPassword() for a method that allows this parameter to be set after the constructor.
dbThe database name for the new connection. Also see Datasource::setDBName() for a method that allows this parameter to be set after the constructor.
encodingThe database-specific name of the character encoding to use for the new connection. Also see Datasource::setDBCharset() for a method that allows this parameter to be set after the constructor. If no value is passed for this parameter, then the database character encoding corresponding to the default character encoding will be used instead.
hostThe host name for the new connection. Also see Datasource::setHostName() for a method that allows this parameter to be set after the constructor.
portThe port number for the new connection. Also see Datasource::setPort() for a method that allows this parameter to be set after the constructor.
optionsAny options for the database driver for the new connection
queueAn optional Queue object to receive datasource events; note that the Queue passed cannot have any maximum size set or a QUEUE-ERROR will be thrown; passing NOTHING will clear any event queue
argan optional argument to be included in the arg key of datasource events
Example:
my Datasource $db(DSPGSQL, "user", "pass", "database", "utf8", "localhost", 5432);
Exceptions
DATASOURCE-UNSUPPORTED-DATABASEDBI driver cannot be loaded
DATASOURCE-CONSTRUCTOR-ERRORport value is <= 0
DBI-OPTION-ERRORunknown or unsupported option passed to driver
Qore::SQL::Datasource::constructor ( string  desc,
*Qore::Thread::Queue  queue,
any  arg 
)

Creates a Datasource object from a single string giving all parameters that can be parsed by parse_datasource()

Parameters
desca datasource description string in the format that can be parsed by parse_datasource()
queueAn optional Queue object to receive datasource events; note that the Queue passed cannot have any maximum size set or a QUEUE-ERROR will be thrown; passing NOTHING will clear any event queue
argan optional argument to be included in the arg key of datasource events
Example:
my Datasource ds("pgsql:user/pass@db01(utf8)%localhost:5432");
Exceptions
DATASOURCE-UNSUPPORTED-DATABASEDBI driver cannot be loaded
DATASOURCE-CONSTRUCTOR-ERROmissing required parameter for connection; port value is <= 0
DBI-OPTION-ERRORunknown or unsupported option passed to driver
Since
Qore 0.8.6
Qore::SQL::Datasource::constructor ( hash  opts,
*Qore::Thread::Queue  queue,
any  arg 
)

Creates a Datasource object from a hash argument giving parameters for the constructor.

Parameters
optsa hash giving parameters for the new datasource with the following possible keys (the "type" key is mandatory, also usable with the output of the parse_datasource() function):
  • type: (*string) The name of the database driver to use; this key is mandatory; if not present, an exception will be raised. See SQL Constants for builtin constants for DBI drivers shipped with Qore, or see the DBI driver documentation to use an add-on driver (this string should be the name of the driver to be loaded)
  • user: (*string) The user name for the new connection. Also see Datasource::setUserName() for a method that allows this parameter to be set after the constructor.
  • pass: (*string) The password for the new connection. Also see Datasource::setPassword() for a method that allows this parameter to be set after the constructor.
  • db: (*string) The database name for the new connection. Also see Datasource::setDBName() for a method that allows this parameter to be set after the constructor.
  • charset: (*string) The database-specific name of the character encoding to use for the new connection. Also see Datasource::setDBCharset() for a method that allows this parameter to be set after the constructor. If no value is passed for this parameter, then the database character encoding corresponding to the default character encoding for the Qore process will be used instead.
  • host: (*string) The host name for the new connection. Also see Datasource::setHostName() for a method that allows this parameter to be set after the constructor.
  • port: (softint) The port number for the new connection. Also see Datasource::setPort() for a method that allows this parameter to be set after the constructor. If this key is present and is 0 then an exception will be raised.
  • options: (*hash) Any options for the new connection
queueAn optional Queue object to receive datasource events; note that the Queue passed cannot have any maximum size set or a QUEUE-ERROR will be thrown; passing NOTHING will clear any event queue
argan optional argument to be included in the arg key of datasource events
Example:
my Datasource $db(("type": DSPGSQL, "user": "username", "pass": "password", "db": "database", "charset": "utf8", "host": "localhost", "port": 5432);
Exceptions
DATASOURCE-UNSUPPORTED-DATABASEDBI driver cannot be loaded
DATASOURCE-CONSTRUCTOR-ERRORmissing or invalid "driver" key, other key name not assigned to a string; port value is <= 0
DBI-OPTION-ERRORunknown or unsupported option passed to driver
Qore::SQL::Datasource::copy ( )

Creates a new Datasource object with the same driver as the original and copies of all the connection parameters.

Example:
my Datasource $new_ds = $ds.copy();
bool Qore::SQL::Datasource::currentThreadInTransaction ( )

Returns True if the current thread is in a transaction (i.e. holds the transaction lock), False if not.

Returns
True if the current thread is in a transaction (i.e. holds the transaction lock), False if not
Code Flags:
CONSTANT
Example:
my bool $b = $db.currentThreadInTransaction();
See also
Datasource::transactionTid()
Since
Qore 0.8.7
*hash Qore::SQL::Datasource::describe ( string  sql,
  ... 
)

Executes an SQL select statement on the server and returns a description of the result set as a hash.

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
...Include any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
a hash describing the result set with the following keys:
  • name: the name of the column
  • type: a string giving the type of the column
  • maxsize: an integer giving the column size
  • native_type: a string giving the native column type
  • internal_id: an integer giving the native column type code
Example:
my *hash $h = $db.describe("select * from example_table where id = 1");
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions
Since
Qore 0.8.9
Qore::SQL::Datasource::destructor ( )

Closes the datasource if it's open (if any operations are in progress, will block until the operations complete) and destroys the object.

Example:
delete $db;
Exceptions
DATASOURCE-TRANSACTION-EXCEPTIONThe Datasource was destroyed while a transaction was still in progress; the transaction will be automatically rolled back
any Qore::SQL::Datasource::exec ( string  sql,
  ... 
)
virtual

Grabs the transaction lock (if autocommit is disabled) and executes an SQL command on the server and returns either the integer row count (for example, for updates, inserts, and deletes) or the data retrieved (for example, if a stored procedure is executed that returns values).

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

Parameters
sqlThe SQL command to execute on the server
...Include any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
The return value depends on the DBI driver; normally, for commands with placeholders, a hash is returned holding the values acquired from executing the SQL statement. For all other commands, normally an integer row count is returned. However, some DBI drivers also allow select statements to be executed through this interface, which would also return a hash (column names) of lists (values for each column).
Example:
my int $rows = $db.exec("insert into table (varchar_col, timestamp_col, blob_col, numeric_col) values (%v, %v, %v, %d)", $string, now(), $binary, 100);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::execRaw ( string  sql)
virtual

Grabs the transaction lock (if autocommit is disabled) and executes an SQL command on the server and returns either the row count (for example, for updates and inserts) or the data retrieved (for example, if a stored procedure is executed that returns values)

This method does not do any variable binding, so it's useful for example for DDL statements etc

Warning:
Using this method to execute pure dynamic SQL many times with different SQL strings (as opposed to using the same string and binding by value instead of dynamic SQL) can affect application performance by prohibiting the efficient usage of the DB server's statement cache. See DB server documentation for variable binding and the SQL statement cache for more information.
Parameters
sqlThe SQL command to execute on the server; this string will not be subjected to any transformations for variable binding
Returns
The return value depends on the DBI driver; normally, for commands with placeholders, a hash is returned holding the values acquired from executing the SQL statement. For all other commands, normally an integer row count is returned. However, some DBI drivers also allow select statements to be executed through this interface, which would also return a hash (column names) of lists (values for each column).
Example:
$db.execRaw("create table my_tab (id number, some_text varchar2(30))");
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

bool Qore::SQL::Datasource::getAutoCommit ( )

Returns the autocommit status for the object.

Returns
the autocommit status for the object
Code Flags:
CONSTANT
Example:
my bool $b = $db.getAutoCommit();
int Qore::SQL::Datasource::getCapabilities ( )

Returns an integer bitfield of DBI driver capabilities.

Returns
an integer bitfield of DBI driver capabilities; see DBI Capability Constants for the meaning of each bit
Code Flags:
CONSTANT
Example:
my int $caps = $db.getCapabilities();
throw "DATASOURCE-ERROR", sprintf("DBI driver %y does not support transaction management", $db.getDriverName());
list Qore::SQL::Datasource::getCapabilityList ( )

Returns a list of strings giving the capabilities of the current DBI driver.

Returns
a list of strings giving the capabilities of the current DBI driver
Code Flags:
CONSTANT
Example:
printf("driver %y has the following capabilities:\n", $db.getDriverName());
foreach my string $cap in ($db.getCapabilityList())
printf("- %s\n", $cap);
any Qore::SQL::Datasource::getClientVersion ( )
virtual

Retrieves the driver-specific client library version information; this method may not be implemented for all drivers.

Returns
the driver-specific client library version information; this method may not be implemented for all drivers; see the DBI driver documentation for the return data type and format
Example:
my any $ver = $db.getClientVersion();
Note
see the documentation for the DBI driver being used for possible exceptions

Implements Qore::SQL::AbstractDatasource.

hash Qore::SQL::Datasource::getConfigHash ( )
virtual

Returns a datasource hash describing the configuration of the current object.

Code Flags:
CONSTANT
Example:
my hash $h = $ds.getConfigHash();
Returns
a datasource hash describing the configuration of the current object
Since
Qore 0.8.8

Implements Qore::SQL::AbstractDatasource.

string Qore::SQL::Datasource::getConfigString ( )
virtual

Returns a string giving the configuration of the current object in a format that can be parsed by parse_datasource()

Code Flags:
CONSTANT
Example:
my string $str = $ds.getConfigString();
Returns
a string giving the configuration of the current object in a format that can be parsed by parse_datasource()
Since
Qore 0.8.8

Implements Qore::SQL::AbstractDatasource.

string Qore::SQL::Datasource::getDBCharset ( )

Retrieves the database-specific charset set encoding for the current connection.

A method synonym for Datasource::getDBEncoding() kept for backwards-compatibility.

Returns
the database-specific charset set encoding for the current connection
Code Flags:
CONSTANT
Example:
my string $enc = $db.getDBCharset();
string Qore::SQL::Datasource::getDBEncoding ( )
virtual

Retrieves the database-specific charset set encoding for the current connection.

Returns
the database-specific charset set encoding for the current connection
Code Flags:
CONSTANT
Example:
my string $enc = $db.getDBEncoding();
See also
Datasource::getOSEncoding();

Implements Qore::SQL::AbstractDatasource.

*string Qore::SQL::Datasource::getDBName ( )
virtual

Returns the database name parameter as a string or NOTHING if none is set.

Returns
the database name parameter as a string or NOTHING if none is set
Code Flags:
CONSTANT
Example:
my *string $db = $db.getDBName();

Implements Qore::SQL::AbstractDatasource.

string Qore::SQL::Datasource::getDriverName ( )
virtual

Returns the name of the driver used for the object.

Returns
the name of the driver used for the object
Code Flags:
CONSTANT
Example:
my string $driver = $db.getDriverName();

Implements Qore::SQL::AbstractDatasource.

*string Qore::SQL::Datasource::getHostName ( )
virtual

Returns the hostname parameter as a string or NOTHING if none is set.

Returns
the hostname parameter as a string or NOTHING if none is set
Code Flags:
CONSTANT
Example:
my *string $host = $db.getHostName();

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::getOption ( string  opt)

Returns the current value for the given option.

Code Flags:
RET_VALUE_ONLY
Parameters
optthe option to get
Note
in order to ensure atomicity when dealing with Datasource options, the transaction lock is acquired before executing this method if it was not already owned by the calling thread
Exceptions
DBI-OPTION-ERRORunknown or unsupported option passed to driver
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Since
Qore 0.8.6
hash Qore::SQL::Datasource::getOptionHash ( )

returns the valid options for the driver associated with the Datasource with descriptions and current values for the current Datasource object

Code Flags:
RET_VALUE_ONLY
Returns
a hash where the keys are valid option names, and the values are hashes with the following keys:
  • "desc": a string description of the option
  • "type": a string giving the data type restriction for the option
  • "value": the current value of the option
Note
in order to ensure atomicity when dealing with Datasource options, the transaction lock is acquired before executing this method if it was not already owned by the calling thread
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Since
Qore 0.8.6
string Qore::SQL::Datasource::getOSCharset ( )

Returns the Qore character encoding name for the current connection as a string or "(unknown)" if none is set.

Returns
the Qore character encoding name for the current connection as a string or "(unknown)" if none is set
Code Flags:
CONSTANT
Example:
my string $enc = $db.getOSCharset();
See also
Datasource::getOSEncoding()
*string Qore::SQL::Datasource::getOSEncoding ( )
virtual

Returns the Qore character encoding name for the current connection as a string or NOTHING if none is set.

Returns
the Qore character encoding for the current connection as a string or NOTHING if none is set
Code Flags:
CONSTANT
Example:
my *string $enc = $db.getOSEncoding();

Implements Qore::SQL::AbstractDatasource.

*string Qore::SQL::Datasource::getPassword ( )
virtual

Returns the password parameter as a string or NOTHING if none is set.

Returns
the password parameter as a string or NOTHING if none is set
Code Flags:
CONSTANT
Example:
my *string $pass = $db.getPassword();

Implements Qore::SQL::AbstractDatasource.

*int Qore::SQL::Datasource::getPort ( )
virtual

Gets the port number that will be used for the next connection to the server.

Invalid port numbers will cause an exception to be thrown when the connection is opened

Code Flags:
CONSTANT
Example:
my *int $port = $db.getPort();

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::getServerVersion ( )
virtual

Returns the driver-specific server version data for the current connection.

Returns
the driver-specific server version data for the current connection; see the DBI driver documentation for the return data type and format
Example:
my any $ver = $db.getServerVersion();
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

int Qore::SQL::Datasource::getTransactionLockTimeout ( )

Retrieves the transaction lock timeout value as an integer in milliseconds.

Returns
the transaction lock timeout value as an integer in milliseconds
Code Flags:
CONSTANT
Example:
my int $to_ms = $db.getTransactionLockTimeout();
*string Qore::SQL::Datasource::getUserName ( )
virtual

Returns the username parameter as a string or NOTHING if none is set.

Returns
the username parameter as a string or NOTHING if none is set
Code Flags:
CONSTANT
Example:
my *string $user = $db.getUserName();

Implements Qore::SQL::AbstractDatasource.

bool Qore::SQL::Datasource::inTransaction ( )
virtual

Returns True if a transaction is currently in progress, False if not.

Returns
True if a transaction is currently in progress, False if not
Code Flags:
CONSTANT
Example:
my bool $b = $db.inTransaction();

Implements Qore::SQL::AbstractDatasource.

nothing Qore::SQL::Datasource::open ( )

Opens a connection to the datasouce, using the connection parameters already set; an exception is thrown if any errors occur.

If the connection is already open, then no action is taken.

Example:
$db.open();
Note
see the documentation for the DBI driver being used for possible exceptions
See also
Datasource::reset()
nothing Qore::SQL::Datasource::reset ( )

Closes and reopens the Datasource.

Example:
$db.reset();
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions
nothing Qore::SQL::Datasource::rollback ( )
virtual

Rolls the current transaction back and releases the transaction lock.

Example:
$db.rollback();
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::select ( string  sql,
  ... 
)
virtual

Executes an SQL select statement on the server and returns the result as a hash (column names) of lists (column values per row)

The return format of this method is suitable for use with context statements, for easy iteration and processing of query results. Alternatively, the HashListIterator class can be used to iterate the return value of this method.

Additionally, this format is a more efficient format than that returned by the Datasource::selectRows() method, because the column names are not repeated for each row returned. Therefore, for retrieving anything greater than small amounts of data, it is recommended to use this method instead of Datasource::selectRows().

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
...Include any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
This method returns a hash (the keys are the column names) of lists (the column data per row) when executed with an SQL select statement, however some DBI drivers allow any SQL to be executed through this method, in which case other data types can be returned (such as an integer for a row count or a hash for output parameters when executing a stored procedure)
Example:
# bind a string and a date/time value by value in a query
$query = $db.select("select * from table where varchar_column = %v and timestamp_column > %v", $string, 2007-10-11T15:31:26.289);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
  • See the documentation for the DBI driver being used for additional possible exceptions
  • This method returns all the data available immediately; to process query data piecewise, use the SQLStatement class
See also

Implements Qore::SQL::AbstractDatasource.

*hash Qore::SQL::Datasource::selectRow ( string  sql,
  ... 
)
virtual

Executes an SQL select statement on the server and returns the first row as a hash (the column values)

If more than one row is returned, then it is treated as an error and a DBI-SELECT-ROW-ERROR is returned (however the DBI driver should raise its own exception here to avoid retrieving more than one row from the server). For a similar method taking a list for all bind arguments, see Datasource::vselectRow().

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
...Include any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
This method returns a hash (the keys are the column names) of row data or NOTHING if no row is found for the query when executed with an SQL select statement
Example:
my *hash $h = $db.selectRow("select * from example_table where id = 1");
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
DBI-SELECT-ROW-ERRORmore than 1 row retrieved from the server
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::selectRows ( string  sql,
  ... 
)
virtual

Executes an SQL select statement on the server and returns the result as a list (rows) of hashes (the column values)

The return format of this method is not as memory efficient as that returned by the Datasource::select() method, therefore for larger amounts of data, it is recommended to use Datasource::select().

The usual return value of this method can be iterated with the ListHashIterator class.

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
...Include any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
Normally returns a list (rows) of hash (where the keys are the column names of each row) or NOTHING if no rows are found for the query, however some DBI drivers allow any SQL statement to be executed through this method (not only select statements), in this case other data types can be returned
Example:
my *list $list = $db.selectRows("select * from example_table");
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
  • See the documentation for the DBI driver being used for additional possible exceptions
  • This method returns all the data available immediately; to process query data piecewise, use the SQLStatement class
See also
Datasource::select()

Implements Qore::SQL::AbstractDatasource.

nothing Qore::SQL::Datasource::setAutoCommit ( bool  ac = True)

Turns autocommit on or off for this object.

Parameters
acTrue to turn on autocommit (a commit will be executed after every SQL call to the server), False to turn off autocommit (commits must be manually triggered)
Example:
$db.setAutoCommit(False);
nothing Qore::SQL::Datasource::setDBCharset ( string  encoding)

Sets the database-specific character encoding name for the next connection to the server.

This is a method synonym for the Datasource::setDBEncoding() method, kept for backwards-compatibility.

Invalid character encoding names will cause an exception to be thrown when the connection is opened.

Parameters
encodingthe database-specific character encoding name for the next connection to the server
Example:
$db.setDBCharset($encoding);
nothing Qore::SQL::Datasource::setDBEncoding ( string  encoding)

Sets the database-specific character encoding name for the next connection to the server.

Invalid character encoding names will cause an exception to be thrown when the connection is opened.

Parameters
encodingthe database-specific character encoding name for the next connection to the server
Example:
$db.setDBEncoding($encoding);
nothing Qore::SQL::Datasource::setDBName ( string  db)

Sets the database name parameter for the time a connection to the server is established.

Invalid database names will cause an exception to be thrown when the connection is opened

Parameters
dbthe database name parameter for the time a connection to the server is established
Example:
$db.setDBName($db);
nothing Qore::SQL::Datasource::setEventQueue ( Qore::Thread::Queue  queue,
any  arg 
)

Sets a queue object for DBI events on the datasource.

Parameters
queuethe Queue object to receive datasource events; note that the Queue passed cannot have any maximum size set or a QUEUE-ERROR will be thrown; passing NOTHING will clear any event queue
argan argument to be included in the arg key of datasource events
Exceptions
QUEUE-ERRORthe Queue passed has a maximum size set
Since
Qore 0.8.9
nothing Qore::SQL::Datasource::setHostName ( string  host)

Sets the hostname to use for the next connection to the server.

Invalid hostnames will cause an exception to be thrown when the connection is opened.

Parameters
hostthe hostname to use for the next connection to the server
Example:
$db.setHostName($host);
Qore::SQL::Datasource::setOption ( string  opt,
any  val 
)

sets an option for the datasource

Parameters
optthe option to set
valthe value to set
Note
in order to ensure atomicity when dealing with Datasource options, the transaction lock is acquired before executing this method if it was not already owned by the calling thread
Exceptions
DBI-OPTION-ERRORunknown or unsupported option passed to driver
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Since
Qore 0.8.6
nothing Qore::SQL::Datasource::setPassword ( string  pass)

Sets the password parameter for the time a connection to the server is established.

Invalid passwords will cause an exception to be thrown when the connection is opened

Parameters
passthe password parameter for the time a connection to the server is established
Example:
$db.setPassword($pass);
nothing Qore::SQL::Datasource::setPort ( softint  port = 0)

Sets the port number to use for the connection.

Invalid port numbers will cause an exception to be thrown when the connection is opened

Parameters
portthe port number to use for the connection
Example:
$db.setPort($port);
nothing Qore::SQL::Datasource::setTransactionLockTimeout ( timeout  timeout_ms = 0)

Sets the transaction lock timeout value in milliseconds; set to 0 for no timeout.

Parameters
timeout_msthe transaction lock timeout value in milliseconds; set to 0 for no timeout. Like all Qore functions and methods taking timeout values, a relative date/time value may be passed instead of an integer to make the timeout units clear (ex: 2500ms for 2.5 seconds).
Example:
$db.setTransactionLockTimeout(4s);
nothing Qore::SQL::Datasource::setUserName ( string  user)

Sets the username parameter for the time a connection to the server is established.

Invalid usernames will cause an exception to be thrown when the connection is opened

Parameters
userthe username parameter for the time a connection to the server is established
Example:
$db.setUserName($user);
int Qore::SQL::Datasource::transactionTid ( )

Returns the TID of the thread holding the transaction lock or -1 if it's not currently held.

If the Datasource object is used in a multithreaded context and if the transaction lock is not held by the current thread, then the transaction lock status could change at any time.

Returns
the TID of the thread holding the transaction lock or -1 if it's not currently held
Code Flags:
CONSTANT
Example:
my int $tid = $db.transactionTid();
See also
Datasource::currentThreadInTransaction()
Since
Qore 0.8.7
any Qore::SQL::Datasource::vexec ( string  sql,
*softlist  vargs 
)
virtual

Grabs the transaction lock (if autocommit is disabled) and executes SQL code on the DB connection, taking a list for all bind arguments.

Same as Datasource::exec() except takes an explicit list for bind arguments

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

Parameters
sqlThe SQL command to execute on the server
vargsInclude any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
The return value depends on the DBI driver; normally, for commands with placeholders, a hash is returned holding the values acquired from executing the SQL statement. For all other commands, normally an integer row count is returned. However, some DBI drivers also allow select statements to be executed through this interface, which would also return a hash (column names) of lists (values for each column).
Example:
my int $rows = $db.vexec("insert into example_table value (%v, %v, %v)", $arg_list);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::vselect ( string  sql,
*softlist  vargs 
)
virtual

Executes a select statement on the server and returns the results in a hash (column names) of lists (column values per row), taking a list for all bind arguments.

The return format of this method is suitable for use with context statements, for easy iteration and processing of query results. Alternatively, the HashListIterator class can be used to iterate the return value of this method.

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
vargsInclude any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
Normally returns a hash (the keys are the column names) of list (each hash key's value is a list giving the row data), however some DBI drivers allow any SQL statement to be executed through this method (not only select statements), in this case other data types can be returned
Example:
my *hash $query = $db.vselect("select * from example_table where id = %v and name = %v", $arg_list);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
  • See the documentation for the DBI driver being used for additional possible exceptions
  • This method returns all the data available immediately; to process query data piecewise, use the SQLStatement class
See also

Implements Qore::SQL::AbstractDatasource.

*hash Qore::SQL::Datasource::vselectRow ( string  sql,
*softlist  vargs 
)
virtual

Executes a select statement on the server and returns the first row as a hash (column names and values), taking a list for all bind arguments.

This method is the same as the Datasource::selectRow() method, except this method takes a single argument after the SQL command giving the list of bind value parameters

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
vargsInclude any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
This method returns a hash (the keys are the column names) of row data or NOTHING if no row is found for the query when executed with an SQL select statement
Example:
my *hash $h = $db.vselectRow("select * from example_table where id = %v and type = %v", $arg_list);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
see the documentation for the DBI driver being used for additional possible exceptions
See also
Datasource::selectRow()

Implements Qore::SQL::AbstractDatasource.

any Qore::SQL::Datasource::vselectRows ( string  sql,
*softlist  vargs 
)
virtual

Executes a select statement on the server and returns the results in a list (rows) of hashes (column names and values), taking a list for all bind arguments.

Same as the Datasource::selectRows() method, except this method takes a single argument after the SQL command giving the list of bind value parameters.

The usual return value of this method can be iterated with the ListHashIterator class.

The return format of this method is not as memory efficient as that returned by the Datasource::select() method, therefore for larger amounts of data, it is recommended to use Datasource::select().

This method also accepts all bind parameters (%d, %v, %s, etc) as documented in Binding by Value and Placeholder

This method does not retain the transaction lock if it was not already acquired before this method is called, so to execute select statements that begin a transaction (such as "select for update"), execute Datasource::beginTransaction() first to ensure that the transaction lock is dedicated to the calling thread.

Parameters
sqlThe SQL command to execute on the server
vargsInclude any values to be bound (using %v in the command string) or placeholder specifications (using :key_name in the command string) in order after the command string
Returns
Normally returns a list (rows) of hash (where the keys are the column names of each row) or NOTHING if no rows are found for the query, however some DBI drivers allow any SQL statement to be executed through this method (not only select statements), in this case other data types can be returned
Example:
my *list $list = $db.vselectRows("select * from example_table where id = %v and type = %v", $arg_list);
Exceptions
TRANSACTION-LOCK-TIMEOUTTimeout trying to acquire the transaction lock
Note
  • See the documentation for the DBI driver being used for additional possible exceptions
  • This method returns all the data available immediately; to process query data piecewise, use the SQLStatement class
See also
Datasource::selectRows()

Implements Qore::SQL::AbstractDatasource.