SQL Operations Guide

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The Server Architecture

On startup, FairCom DB SQL will attempt to load the FairCom DB SQL dynamic callback library when the SQL_OPTION LOAD_CALLBACK_LIB configuration option is specified in the server configuration file, ctsrvr.cfg.

Note: For Windows systems, the dynamic callback library is named ctsqlcbk.dll. For Unix-based systems, the dynamic callback library is named libctsqlcbk with a filename extention appropriate to that operating system's default shared library conventions (.so, .sl., .dynlib, etc.).

The diagram below depicts the relationship of FairCom DB SQL with the callback library and its configuration file:

If the callback library is not found, no messages are reported because the dynamic library is not required for normal FairCom DB SQL operation, however, types conversion will not take place.

If the callback library is located and loaded, the following steps are taken:

  • The ctsqlcbk.ini configuration file is loaded and parsed;
  • The appropriate c-treeDB API callbacks are established;

Windows and Unix-based systems use different methods for locating dynamic libraries. In Windows systems, dynamic libraries are called DLLs - Dynamic Link Libraries (.dll), while Unix-based systems use the term Shared Libraries (.so, .sl). Please refer to the FairCom DB SQL Callback Dynamic Library section below for detailed information on the use of the libraries on Windows and Unix-based systems.

The configuration file is described in detail in the FairCom DB SQL Configuration section.