dbExpress Database Specific Information
Go Up to Developing Database Applications for the Win32 Platform Index
dbExpress is a general database framework that allows connecting to a variety of supported databases. Databases may vary in various respects, such as data types. This topic supplies information you need to work with different databases.
Contents
Interbase
Support
Both Interbase 2009 and Interbase 2007 are supported. This includes driver support, TField support, and DataExplorer support.
To-Go
dbExpress also supports the InterBase To-Go Edition, which is a small, portable version of the Desktop Edition. Target applications for the To-Go Edition include small devices and public kiosks, as well as Value Added Reseller (VAR) applications that were built using InterBase. Used in the To-Go edition form, InterBase does not have to be separately installed on any server or end-user workstation.
dbxdrivers.ini Setting
In the [Interbase] section, you need to set VendorLib.
For Interbase:
VendorLib=GDS32.DLL
For To-Go:
VendorLib=IBTOGO.DLL
MS SQL
Support
MS SQL Server 2008 is fully supported. You must install the MS SQL Server 2008 native client, not MS SQL Server 2005. This client includes sqlncli10.dll, not oledb.dll. You can download the client from [1] under the Microsoft SQL Server 2008 Native Client section.
MSSQL Driver Requires Calls to CoInitialize and CoUninitialize for Console Applications and Worker Threads
The MSSQL driver does not call CoInitialize or CoUninitialize. Earlier versions of the MSSQL driver, which is a COM driver, called CoInitialize and CoUninitialize directly, which is not a good practice. VCL applications take care of these calls for you, so VCL applications do not require calling CoInitialize and CoUninitialize.
However, applications using the MSSQL driver in console applications or in worker threads need to call CoInitialize/CoUninitialize. If this call is not made, you will see the following error message:
"DBX Error: Driver could not be properly initialized. Client library may be missing, not installed properly, of the wrong version, or the driver may be missing from the system path."
For help on CoInitialize, see the CoInitialize Function on MSDN.
MYSQL
Support
MYSQL Client 5.1 is both supported and required. If you attempt to connect using an earlier version of the client, the connection fails with this error message:
"Cannot load libraryName library (error code nnn). The libraryName library may be missing from the system path or you may have an incompatible version of the library installed."