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Technical Reference


Technical Reference


ODBC Versions Supported

The Easysoft ODBC-ODBC Bridge supports most of ODBC 2.0 and ODBC 2.5, and all of ODBC 3.0. All the ODBC 2.0 and 2.5 API required to run Perl DBD:ODBC, PHP or mxODBC is present, but the full API of these deprecated versions is not supported as new applications will be written using the ODBC 3.0 API. The ODBC 3.0 API is supported in its entirety.


ODBC API Supported

This section documents the ODBC-ODBC Bridge API where it differs to the ODBC API.

Modifications to the API

On non-Windows platforms SQLDrivers is implemented by the ODBC-ODBC Bridge even though it is a driver manager function. This is primarily for Perl DBD::ODBC 0.21 support. The ODBC-ODBC Bridge only returns details about itself and no other drivers.

SQLBrowseConnect is a slightly uncomfortable API in the context of an ODBC-ODBC bridge. Normally, SQLBrowseConnect provides an iterative method of discovering and enumerating the attributes and attribute values required to connect to a data source. Each call to SQLBrowseConnect returns successive levels of attributes and attribute values. When all levels have been enumerated, a connection to the data source is completed and a complete connection string is returned by SQLBrowseConnect.

This process works fine when SQLBrowseConnect is called for a driver on the local machine but when you introduce a bridge there are in effect two levels of browsing. The first level will browse the local datasources (defined in your odbc.ini file or the registry) but these point to another real datasource on a remote machine.

For this release of the Easysoft ODBC-ODBC Bridge, SQLBrowseConnect only supports browsing the OOB data sources on the local machine. If the user then selects one of these to connect to, they will be prompted for ODBC-ODBC Bridge attributes such as SERVER, TRANSPORT, PORT, LOGINUSER, LOGINAUTH, TARGETUSER and TARGETAUTH.

Once sufficient attributes have been defined to allow a bridge connection to the server, the server side of the OOB will return a list of DSNs retrieved by calling SQLDataSources. The browse stops here and so the remote datasource must already be set up with sufficient information to allow a connection.

This implementation avoids complications with possible clashes of attributes between the OOB and the remote ODBC driver which would make it impossible to return a final connection string which allows a later connection without browsing.

Extra functions

The non-Windows version of the Easysoft ODBC-ODBC Bridge contains extra functions which are not part of the ODBC API. These were created as a substitute for the valuable functionality of SQLDataSources which was not implemented in early pre-releases. They are listed below:

The ODBC-ODBC Bridge now supports SQLDataSources so these functions are deprecated.

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