SQLDisconnect Function

Conformance
Version Introduced: ODBC 1.0 Standards Compliance: ISO 92

Summary
SQLDisconnect closes the connection associated with a specific connection handle.

Syntax

  
SQLRETURN SQLDisconnect(  
     SQLHDBC     ConnectionHandle);  

Arguments

ConnectionHandle
[Input] Connection handle.

Returns

SQL_SUCCESS, SQL_SUCCESS_WITH_INFO, SQL_ERROR, SQL_INVALID_HANDLE, or SQL_STILL_EXECUTING.

Diagnostics

When SQLDisconnect returns SQL_ERROR or SQL_SUCCESS_WITH_INFO, an associated SQLSTATE value may be obtained by calling SQLGetDiagRec with a HandleType of SQL_HANDLE_DBC and a Handle of ConnectionHandle. The following table lists the SQLSTATE values commonly returned by SQLDisconnect and explains each one in the context of this function; the notation "(DM)" precedes the descriptions of SQLSTATEs returned by the Driver Manager. The return code associated with each SQLSTATE value is SQL_ERROR, unless noted otherwise.

SQLSTATE	Error	Description
01000	General warning	Driver-specific informational message. (Function returns SQL_SUCCESS_WITH_INFO.)
01002	Disconnect error	An error occurred during the disconnect. However, the disconnect succeeded. (Function returns SQL_SUCCESS_WITH_INFO.)
08003	Connection not open	(DM) The connection specified in the argument ConnectionHandle was not open.
25000	Invalid transaction state	There was a transaction in process on the connection specified by the argument ConnectionHandle. The transaction remains active.
HY000	General error	An error occurred for which there was no specific SQLSTATE and for which no implementation-specific SQLSTATE was defined. The error message returned by SQLGetDiagRec in the *MessageText buffer describes the error and its cause.
HY001	Memory allocation error	The driver was unable to allocate memory required to support execution or completion of the function.
HY008	Operation canceled	Asynchronous processing was enabled for the ConnectionHandle. The function was called, and before it finshed executing SQLCancelHandle Function was called on the ConnectionHandle. Then the function was called again on the ConnectionHandle. The function was called, and before it finished executing SQLCancelHandle was called on the ConnectionHandle from a different thread in a multithread application.
HY010	Function sequence error	(DM) An asynchronously executing function was called for a StatementHandle associated with the ConnectionHandle and was still executing when SQLDisconnect was called. (DM) An asynchronously executing function (not this one) was called for the ConnectionHandle and was still executing when this function was called. (DM) SQLExecute, SQLExecDirect, SQLBulkOperations, or SQLSetPos was called for a StatementHandle associated with the ConnectionHandle and returned SQL_NEED_DATA. This function was called before data was sent for all data-at-execution parameters or columns.
HY013	Memory management error	The function call could not be processed because the underlying memory objects could not be accessed, possibly because of low memory conditions.
HY117	Connection is suspended due to unknown transaction state. Only disconnect and read-only functions are allowed.	(DM) For more information about suspended state, see SQLEndTran Function.
HYT01	Connection timeout expired	The connection timeout period expired before the data source responded to the request, and the connection is still active. The connection timeout period is set through SQLSetConnectAttr, SQL_ATTR_CONNECTION_TIMEOUT.
IM001	Driver does not support this function	(DM) The driver associated with the ConnectionHandle does not support the function.
IM017	Polling is disabled in asynchronous notification mode	Whenever the notification model is used, polling is disabled.
IM018	SQLCompleteAsync has not been called to complete the previous asynchronous operation on this handle.	If the previous function call on the handle returns SQL_STILL_EXECUTING and if notification mode is enabled, SQLCompleteAsync must be called on the handle to do post-processing and complete the operation.

Comments

If an application calls SQLDisconnect after SQLBrowseConnect returns SQL_NEED_DATA and before it returns a different return code, the driver cancels the connection browsing process and returns the connection to an unconnected state.

If an application calls SQLDisconnect while there is an incomplete transaction associated with the connection handle, the driver returns SQLSTATE 25000 (Invalid transaction state), indicating that the transaction is unchanged and the connection is open. An incomplete transaction is one that has not been committed or rolled back with SQLEndTran.

If an application calls SQLDisconnect before it has freed all statements associated with the connection, the driver, after it successfully disconnects from the data source, frees those statements and all descriptors that have been explicitly allocated on the connection. However, if one or more of the statements associated with the connection are still executing asynchronously, SQLDisconnect returns SQL_ERROR with a SQLSTATE value of HY010 (Function sequence error). Also, SQLDisconnect will free all associated statements and all descriptors that have been explicitly allocated on the connection, if the connection is in a suspended state or if SQLDisconnect was successfully canceled by SQLCancelHandle.

For information about how an application uses SQLDisconnect, see Disconnecting from a Data Source or Driver.

Disconnecting from a Pooled Connection

If connection pooling is enabled for a shared environment and an application calls SQLDisconnect on a connection in that environment, the connection is returned to the connection pool and is still available to other components using the same shared environment.

Code Example

See Sample ODBC Program, SQLBrowseConnect Function, and SQLConnect Function.

Related Functions

For information about	See
Allocating a handle	SQLAllocHandle Function
Connecting to a data source	SQLConnect Function
Connecting to a data source using a connection string or dialog box	SQLDriverConnect Function
Executing a commit or rollback operation	SQLEndTran Function
Freeing a connection handle	SQLFreeConnect Function

See Also

ODBC API Reference
ODBC Header Files