Using CitectSCADA > Exchanging Data with Other Applications > Using ODBC drivers > About the ODBC driver

About the ODBC driver

CitectSCADA connects directly to the Microsoft Access ODBC driver, which allows applications to access information stored in MDB (Microsoft Access Database) files without actually running Microsoft Access. (Microsoft Access uses the "Jet Engine" DLL to access information stored in MDB files.)

ODBC normally implies heavy use of SQL statements to manipulate data. SQL statements can become quite complex and verbose. To implement them in Cicode they often have to be separated into sub-strings so that the maximum string length for Cicode variables is not exceeded.

With Access, it is possible to call queries that have been defined in Access so that the SQL statements become quite simple and straightforward. The Access tables & queries can be used to implement RELATIONSHIPS and JOINS, to SORT & SELECT only those rows (records) and return only those columns (fields) of particular interest at the time.

Developing queries in Access also has an advantage that the resulting Recordsets can be viewed in Access to test that they contain the data that is expected. The queries can incorporate SQL Functions (such as BETWEEN & AND).

The Jet Engine can also call upon theVBA Expression Service. This means that many non ANSI functions can also be used (both in SQL statements and Access Query Definitions) provided there is no need to migrate to a non Access system at a later date. Refer to VBA Functions Reference in the Access or Excel help system (only those functions with (VBA) after them and are appropriate to an SQL environment, are likely to work in an SQL statement).

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