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SQLAllocHandle

Updated at: Jul 15, 2020 GMT+08:00

Function

SQLAllocHandle allocates environment, connection, or statement handles. This function is a generic function for allocating handles that replaces the deprecated ODBC 2.x functions SQLAllocEnv, SQLAllocConnect, and SQLAllocStmt.

Prototype

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SQLRETURN SQLAllocHandle(SQLSMALLINT   HandleType,    
                         SQLHANDLE     InputHandle,     
                         SQLHANDLE     *OutputHandlePtr);

Parameter

Table 1 SQLAllocHandle parameters

Keyword

Description

HandleType

The type of handle to be allocated by SQLAllocHandle. The value must be one of the following:

  • SQL_HANDLE_ENV (environment handle)
  • SQL_HANDLE_DBC (connection handle)
  • SQL_HANDLE_STMT (statement handle)
  • SQL_HANDLE_DESC (description handle)

The handle application sequence is: SQL_HANDLE_ENV > SQL_HANDLE_DBC > SQL_HANDLE_STMT. The handle applied later depends on the handle applied prior to it.

InputHandle

Existing handle to use as a context for the new handle being allocated.

  • If HandleType is SQL_HANDLE_ENV, this is SQL_NULL_HANDLE.
  • If HandleType is SQL_HANDLE_DBC, this must be an environment handle.
  • If HandleType is SQL_HANDLE_STMT or SQL_HANDLE_DESC, it must be a connection handle.

OutputHandlePtr

Output parameter: Pointer to a buffer in which to return the handle to the newly allocated data structure.

Return Values

  • SQL_SUCCESS indicates that the call succeeded.
  • SQL_SUCCESS_WITH_INFO indicates some warning information is displayed.
  • SQL_ERROR indicates major errors, such as memory allocation and connection failures.
  • SQL_INVALID_HANDLE indicates that invalid handles were called. Values returned by other APIs are similar to the preceding values.

Precautions

When allocating a non-environment handle, if SQLAllocHandle returns SQL_ERROR, it sets OutputHandlePtr to SQL_NULL_HENV, SQL_NULL_HDBC, SQL_NULL_HSTMT, or SQL_NULL_HDESC. The application can then call SQLGetDiagRec, with HandleType and Handle set to IntputHandle, to obtain the SQLSTATE value. The SQLSTATE value provides the detailed function calling information.

Examples

See Examples.

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