.. module:: cx_Oracle .. _module: **************** Module Interface **************** .. function:: Binary(string) Construct an object holding a binary (long) string value. .. function:: clientversion() Return the version of the client library being used as a 5-tuple. The five values are the major version, minor version, update number, patch number and port update number. .. note:: This method is an extension to the DB API definition and is only available in Oracle 10g Release 2 and higher. .. function:: Connection([user, password, dsn, mode, handle, pool, threaded, twophase]) connect([user, password, dsn, mode, handle, pool, threaded, twophase]) Constructor for creating a connection to the database. Return a Connection object (:ref:`connobj`). All arguments are optional and can be specified as keyword parameters. The dsn (data source name) is the TNS entry (from the Oracle names server or tnsnames.ora file) or is a string like the one returned from makedsn(). If only one parameter is passed, a connect string is assumed which is to be of the format ``user/password@dsn``, the same format accepted by Oracle applications such as SQL\*Plus. If the mode is specified, it must be one of :data:`SYSDBA` or :data:`SYSOPER` which are defined at the module level; otherwise it defaults to the normal mode of connecting. If the handle is specified, it must be of type OCISvcCtx\* and is only of use when embedding Python in an application (like PowerBuilder) which has already made the connection. The pool is only valid in Oracle 9i and is a session pool object (:ref:`sesspool`) which is the equivalent of calling pool.acquire(). The threaded attribute is expected to be a boolean expression which indicates whether or not Oracle should use the mode OCI_THREADED to wrap accesses to connections with a mutex. Doing so in single threaded applications imposes a performance penalty of about 10-15% which is why the default is False. The twophase attribute is expected to be a boolean expression which indicates whether or not the attributes should be set on the connection object to allow for two phase commit. The default for this value is also False because of bugs in Oracle prior to Oracle 10g. .. function:: Cursor(connection) Constructor for creating a cursor. Return a new Cursor object (:ref:`cursorobj`) using the connection. .. note:: This method is an extension to the DB API definition. .. function:: Date(year, month, day) Construct an object holding a date value. .. function:: DateFromTicks(ticks) Construct an object holding a date value from the given ticks value (number of seconds since the epoch; see the documentation of the standard Python time module for details). .. function:: makedsn(host, port, sid) Return a string suitable for use as the dsn for the connect() method. This string is identical to the strings that are defined by the Oracle names server or defined in the tnsnames.ora file. .. note:: This method is an extension to the DB API definition. .. function:: SessionPool(user, password, database, min, max, increment, [connectiontype, threaded, getmode=cx_Oracle.SPOOL_ATTRVAL_NOWAIT, homogeneous=True]) Create a session pool (see Oracle 9i documentation for more information) and return a session pool object (:ref:`sesspool`). This allows for very fast connections to the database and is of primary use in a server where the same connection is being made multiple times in rapid succession (a web server, for example). If the connection type is specified, all calls to acquire() will create connection objects of that type, rather than the base type defined at the module level. The threaded attribute is expected to be a boolean expression which indicates whether or not Oracle should use the mode OCI_THREADED to wrap accesses to connections with a mutex. Doing so in single threaded applications imposes a performance penalty of about 10-15% which is why the default is False. .. note:: This method is an extension to the DB API definition and is only available in Oracle 9i. .. function:: Time(hour, minute, second) Construct an object holding a time value. .. function:: TimeFromTicks(ticks) Construct an object holding a time value from the given ticks value (number of seconds since the epoch; see the documentation of the standard Python time module for details). .. function:: Timestamp(year, month, day, hour, minute, second) Construct an object holding a time stamp value. .. function:: TimestampFromTicks(ticks) Construct an object holding a time stamp value from the given ticks value (number of seconds since the epoch; see the documentation of the standard Python time module for details). .. _constants: Constants ========= .. data:: apilevel String constant stating the supported DB API level. Currently '2.0'. .. data:: buildtime String constant stating the time when the binary was built. .. note:: This attribute is an extension to the DB API definition. .. data:: BINARY This type object is used to describe columns in a database that are binary (in Oracle this is RAW columns). .. data:: BFILE This type object is used to describe columns in a database that are BFILEs. .. note:: This attribute is an extension to the DB API definition. .. data:: BLOB This type object is used to describe columns in a database that are BLOBs. .. note:: This attribute is an extension to the DB API definition. .. data:: CLOB This type object is used to describe columns in a database that are CLOBs. .. note:: This attribute is an extension to the DB API definition. .. data:: CURSOR This type object is used to describe columns in a database that are cursors (in PL/SQL these are known as ref cursors). .. note:: This attribute is an extension to the DB API definition. .. data:: DATETIME This type object is used to describe columns in a database that are dates. .. data:: DBSHUTDOWN_ABORT This constant is used in database shutdown to indicate that the program should not wait for current calls to complete or for users to disconnect from the database. Use only in unusual circumstances since database recovery may be necessary upon next startup. .. note:: This attribute is an extension to the DB API definition. .. data:: DBSHUTDOWN_FINAL This constant is used in database shutdown to indicate that the instance can be truly halted. This should only be done after the database has been shut down in one of the other modes (except abort) and the database has been closed and dismounted using the appropriate SQL commands. See the method :meth:`~Connection.shutdown()` in the section on connections (:ref:`connobj`). .. note:: This attribute is an extension to the DB API definition. .. data:: DBSHUTDOWN_IMMEDIATE This constant is used in database shutdown to indicate that all uncommitted transactions should be rolled back and any connected users should be disconnected. .. note:: This attribute is an extension to the DB API definition. .. data:: DBSHUTDOWN_TRANSACTIONAL This constant is used in database shutdown to indicate that further connections should be prohibited and no new transactions should be allowed. It then waits for active transactions to complete. .. note:: This attribute is an extension to the DB API definition. .. data:: DBSHUTDOWN_TRANSACTIONAL_LOCAL This constant is used in database shutdown to indicate that further connections should be prohibited and no new transactions should be allowed. It then waits for only local active transactions to complete. .. note:: This attribute is an extension to the DB API definition. .. data:: FIXED_CHAR This type object is used to describe columns in a database that are fixed length strings (in Oracle this is CHAR columns); these behave differently in Oracle than varchar2 so they are differentiated here even though the DB API does not differentiate them. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_BINDBYNAME This constant is used to register callbacks on the OCIBindByName() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_BINDBYPOS This constant is used to register callbacks on the OCIBindByPos() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_DEFINEBYPOS This constant is used to register callbacks on the OCIDefineByPos() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_STMTEXECUTE This constant is used to register callbacks on the OCIStmtExecute() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_STMTFETCH This constant is used to register callbacks on the OCIStmtFetch() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: FNCODE_STMTPREPARE This constant is used to register callbacks on the OCIStmtPrepare() function of the OCI. .. note:: This attribute is an extension to the DB API definition. .. data:: LOB This type object is the Python type of :data:`BLOB` and :data:`CLOB` data that is returned from cursors. .. note:: This attribute is an extension to the DB API definition. .. data:: LONG_BINARY This type object is used to describe columns in a database that are long binary (in Oracle these are LONG RAW columns). .. note:: This attribute is an extension to the DB API definition. .. data:: LONG_STRING This type object is used to describe columns in a database that are long strings (in Oracle these are LONG columns). .. note:: This attribute is an extension to the DB API definition. .. data:: NATIVE_FLOAT This type object is used to describe columns in a database that are of type binary_double or binary_float and is only available in Oracle 10g. .. note:: This attribute is an extension to the DB API definition. .. data:: NCLOB This type object is used to describe columns in a database that are NCLOBs. .. note:: This attribute is an extension to the DB API definition. .. data:: NUMBER This type object is used to describe columns in a database that are numbers. .. data:: OBJECT This type object is used to describe columns in a database that are objects. .. note:: This attribute is an extension to the DB API definition. .. data:: paramstyle String constant stating the type of parameter marker formatting expected by the interface. Currently 'named' as in 'where name = :name'. .. data:: ROWID This type object is used to describe the pseudo column "rowid". .. data:: PRELIM_AUTH This constant is used to define the preliminary authentication mode required for performing database startup and shutdown. .. note:: This attribute is an extension to the DB API definition. .. data:: SPOOL_ATTRVAL_FORCEGET This constant is used to define the "get" mode on session pools and indicates that a new connection will be returned if there are no free sessions available in the pool. .. note:: This attribute is an extension to the DB API definition. .. data:: SPOOL_ATTRVAL_NOWAIT This constant is used to define the "get" mode on session pools and indicates that an exception is raised if there are no free sessions available in the pool. .. note:: This attribute is an extension to the DB API definition. .. data:: SPOOL_ATTRVAL_WAIT This constant is used to define the "get" mode on session pools and indicates that the acquisition of a connection waits until a session is freed if there are no free sessions available in the pool. .. note:: This attribute is an extension to the DB API definition. .. data:: STRING This type object is used to describe columns in a database that are strings (in Oracle this is VARCHAR2 columns). .. data:: SYSDBA Value to be passed to the connect() method which indicates that SYSDBA access is to be acquired. See the Oracle documentation for more details. .. note:: This attribute is an extension to the DB API definition. .. data:: SYSOPER Value to be passed to the connect() method which indicates that SYSOPER access is to be acquired. See the Oracle documentation for more details. .. note:: This attribute is an extension to the DB API definition. .. data:: threadsafety Integer constant stating the level of thread safety that the interface supports. Currently 2, which means that threads may share the module and connections, but not cursors. Sharing means that a thread may use a resource without wrapping it using a mutex semaphore to implement resource locking. Note that in order to make use of multiple threads in a program which intends to connect and disconnect in different threads, the threaded argument to the Connection constructor must be a true value. See the comments on the Connection constructor for more information (:ref:`module`). .. data:: TIMESTAMP This type object is used to describe columns in a database that are timestamps. .. note:: This attribute is an extension to the DB API definition and is only available in Oracle 9i. .. data:: UCBTYPE_ENTRY This constant is used to register callbacks on entry to the function of the OCI. In other words, the callback will be called prior to the execution of the OCI function. .. note:: This attribute is an extension to the DB API definition. .. data:: UCBTYPE_EXIT This constant is used to register callbacks on exit from the function of the OCI. In other words, the callback will be called after the execution of the OCI function. .. note:: This attribute is an extension to the DB API definition. .. data:: UCBTYPE_REPLACE This constant is used to register callbacks that completely replace the call to the OCI function. .. note:: This attribute is an extension to the DB API definition. .. data:: version String constant stating the version of the module. Currently '|release|'. .. note:: This attribute is an extension to the DB API definition. .. _exceptions: Exceptions ========== .. exception:: Warning Exception raised for important warnings and defined by the DB API but not actually used by cx_Oracle. .. exception:: Error Exception that is the base class of all other exceptions defined by cx_Oracle and is a subclass of the Python StandardError exception (defined in the module exceptions). .. exception:: InterfaceError Exception raised for errors that are related to the database interface rather than the database itself. It is a subclass of Error. .. exception:: DatabaseError Exception raised for errors that are related to the database. It is a subclass of Error. .. exception:: DataError Exception raised for errors that are due to problems with the processed data. It is a subclass of DatabaseError. .. exception:: OperationalError Exception raised for errors that are related to the operation of the database but are not necessarily under the control of the progammer. It is a subclass of DatabaseError. .. exception:: IntegrityError Exception raised when the relational integrity of the database is affected. It is a subclass of DatabaseError. .. exception:: InternalError Exception raised when the database encounters an internal error. It is a subclass of DatabaseError. .. exception:: ProgrammingError Exception raised for programming errors. It is a subclass of DatabaseError. .. exception:: NotSupportedError Exception raised when a method or database API was used which is not supported by the database. It is a subclass of DatabaseError. Exception handling ================== .. note:: PEP 249 (Python Database API Specification v2.0) says the following about exception values: [...] The values of these exceptions are not defined. They should give the user a fairly good idea of what went wrong, though. [...] With cx_Oracle every exception object has exactly one argument in the ``args`` tuple. This argument is a ``cx_Oracle._Error`` object which has the following three read-only attributes. .. attribute:: _Error.code Integer attribute representing the Oracle error number (ORA-XXXXX). .. attribute:: _Error.message String attribute representing the Oracle message of the error. This message is localized by the environment of the Oracle connection. .. attribute:: _Error.context String attribute representing the context in which the exception was raised.. This allows you to use the exceptions for example in the following way: :: import sys import cx_Oracle connection = cx_Oracle.Connection("user/pw@tns") cursor = connection.cursor() try: cursor.execute("select 1 / 0 from dual") except cx_Oracle.DatabaseError, exc: error, = exc.args print >> sys.stderr, "Oracle-Error-Code:", error.code print >> sys.stderr, "Oracle-Error-Message:", error.message