Databases

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Revision as of 10:09, 28 August 2011 by BigChimp (talk | contribs) (→‎Supported databases: SQLDB for Interbase; moved Interbase next to Firebird, before ODBC)
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Work in progress..

Databases portal

References:

Tutorials/practical articles:

Databases

Advantage - MySQL - MSSQL - Postgres - Interbase - Firebird - Oracle - ODBC - Paradox - SQLite - dBASE - MS Access - Zeos

Introduction

This page is an introduction to the topic 'Lazarus and databases'. The following table provides an overview of supported databases. Warning: You should only install the database components for which you have the client libraries installed (if the database needs client libaries). Otherwise Lazarus could fail to start because of missing files. You would then have to reinstall Lazarus, because uninstalling the component isn't possible.

Supported databases

Database Package name Need client lib? Need server? Supported versions Supported platforms
Textfiles sdf No No - All
In memory memds No No - All
In memory bufdataset No No - All
DBase DBFLaz No No III+, IV, VII All
FoxPro DBFLaz No No 2.0, 2.5, 3.0 (not completely) All
Paradox TParadoxDataSet No No up to Table Level 7 (and up ??) All
SQLite SQLite Yes No - i386: Linux, Win32
MySQL SQLdb Yes Yes 3.0 - 5.1 i386: Linux, Win32
Firebird SQLdb Yes Depends1) 1 - 2.5 i386: Linux, Win32
Interbase SQLdb Yes Yes 4 - 6 i386: Linux, Win32
PostgreSQL SQLdb Yes Yes 6.6 - 8 i386: Linux, Win32
ODBC SQLdb Yes Depends 3.x 2) i386: Linux, Win32
Oracle SQLdb Yes Yes - -
Advantage TAdsDataSet Yes No 10.1 and greater i386: Linux, Win32

1) You can use an embedded version of Firebird on Windows at least (possibly on Linux/OSX with some tweaking), or you can connect to a Firebird server running on Windows/Unix/OSX/FreeBSD/other Firebird supported platforms

2) This version number refers to the ODBC standard, not to the version number of a driver or driver manager. There are ODBC 3.x drivers for most DBMSs.

The bindings to the database clients

If you want to use one of the databases that need client libraries, those libraries have to be installed. Not only on the computer you're programming on, but also on the computers where the application must run. Note that some databases (in particular MySQL) only work if the bindings which are compiled in the application are from the same version as those of the installed libraries. You can find out how to install those libraries (.so files on *nix systems, and .dlls on windows) on the website of the database developers. The binding units can be found in the packages/base directory in the fpc-sources. They basically consist of the client API calls like mysql_connect_database, which are completely different for each database. It is possible to write database applications using these units, but it is usually far more work and bug-sensitive than using the DB-unit Lazarus components.

Most of these bindings packages are hard-linked to the client libraries. This means that if the application is compiled with one of these units in it, the whole application can not be linked if the client libraries are not available on the workstation. This means that your program executable will not be generated if you do not have installed - for example - a MySQL client on your computer, and you are using the mysql4.pp unit in your program. If you succeed in compiling the program on a computer which has the MySQL client libraries installed, it still won't start on any other machine without the appropriate MySQL client libraries. In other words: for these databases, you need to install client libraries on your development machine, and you need to install these client libraries with your application.

To avoid such problems some of the packages are also able to link dynamically to the libraries. Before any calls to those libraries can be made, the unit has to be 'initialized'. This initialization fails if the database client isn't installed on the computer. If the program is ready using the client library, the unit has to be 'released'.

Running FPC database tests

FreePascal database components include a test framework that can be used to verify functionality. See the directory source\packages\fcl-db\tests\ in your FPC source tree. Included is a test framework that can be run on various database components, as well as some other tests (e.g. test of database export in XMLXSDExportTest.lpr).

To run the test framework on a certain database:

1. Save source\packages\fcl-db\tests\database.ini.txt as source\packages\fcl-db\tests\database.ini

2. Modify source\packages\fcl-db\tests\database.ini to choose which database type you will use.

Example: use Interbase or Firebird: [Database] type=interbase

3. In the same file, customize settings for your database. E.g. if you chose interbase before:

[interbase] connector=sql connectorparams=interbase

name of the database. obviously change to your own playground database

name=testdb user=sysdba password=masterkey

your hostname may very will differ to

hostname=192.168.0.42

4. Compile and run source\packages\fcl-db\tests\dbtestframework.pas The output will be in XML format.

Please see source\packages\fcl-db\tests\README.txt for more details.

Database packages contained in Lazarus

sqldblaz.lpk

This package provides access to different databases (e.g. MySQL or Interbase/Firebird). The components (TSQLQuery, TSQLTransaction, TIBConnection, TODBCConnection, TOracleConnection, TMySQL40Connection, TMySQL41Connection, TMySQL50Connection, TPQConnection) are on the 'SQLdb' tab in the component palette.

dbflaz.lpk

This package provides access to dBase and FoxPro databases. You can get more information in the Lazarus Tdbf Tutorial. The TDbf component is on the 'Data Access' tab in the component palette.

sqlitelaz.lpk

This package provides access to SQLite databases. You can get more information in the Lazarus Database Tutorial.

sdflaz.lpk

The component TSdfDataSet can be found on the 'Data Access' tab in the component palette.

lazreport.lpk

The homepage of the report generator is http://lazreport.sourceforge.net/. More informationen (et al. an additional link) can be found here. LazReport depends on the Printer4Lazarus package. With revision 11950 LazReport was included in the Lazarus SVN repository.

External packages / libraries

Zeos DataBase Objects

These components provide access to different databases. You can find more information here. This wiki also contains a Zeos tutorial.

Pascal Data Objects

There is now an alternative.

Support:

  • MySQL 4.1 and 5.0
  • sqlite-2 and sqlite-3
  • pgsql-8.1
  • interbase-5, interbase-6, firebird-1.0, firebird-1.5, firebird-1.5E, firebird-2.0, firebird-2.0E
  • mssql (Microsoft library) and sybase (FreeTDS library)
  • oracle

like prepared statements, binding, and stored procedures are supported by database API called Pascal Data Objects, which is inspired by PHP Data Objects. All the code and documentation necessary to use this new API is available on Sourceforge:

http://pdo.sourceforge.net

TPSQL

These components provide access via TCP/IP to PostgreSQL databases. You can find more information on this page.

FIBL

These components provide access to Interbase and Firebird databases. The homepage is http://sourceforge.net/projects/fibl.

IBX

IBX For Lazarus are components to access Firebird databases: see IBX

FBLib Firebird Library

FBLib is an open Source Library No Data Aware for direct access to Firebird Relational Database from Borland Delphi/Kylix, Free Pascal and Lazarus.

Current Features include:

  • Direct Access to Firebird 1.0.x, 1.5.x and 2.x Classic or SuperServer
  • Multiplatform [Win32,Gnu/Linux,FreeBSD)
  • Automatic select client library 'fbclient' or 'gds32'
  • Query with params
  • Support SQL Dialect 1/3
  • LGPL License agreement
  • Extract Metadata
  • Simple Script Parser
  • Only 100-150 KB added into final EXE
  • Support BLOB Fields
  • Export Data to HTML SQL Script
  • Service manager (backup,restore,gfix...)
  • Events Alerter

You can download documentation on FBLib's website.

Unified Interbase

UIB provides access to Interbase, Firebird and YAFFIL databases. The homepage is www.progdigy.com. A svn repository is available under https://uib.svn.sourceforge.net/svnroot/uib .

TechInsite Object Persistence Framework (tiOPF)

More information about tiOPF can be found on this page.

Advantage TDataSet Descendant

The Advantage TDataSet Descedant provides a means of connecting to (and opening tables with) the Advantage Database Server. Advantage is a flexible, administration-free embedded database that provides Client/Server as well as Peer-to-peer access to Clipper, FoxPro and Visual FoxPro 9 DBF file formats, as well as a proprietary file format that provides a migration path allowing the use of newer features.

Key Features:

  • Royalty-free peer-to-peer database access with migration path to Client/Server
  • Multi-Platform (Clients supported on Windows and Linux, Server supported on Windows, Linux, and NetWare)
  • Supports Both navigational and relational SQL database access
  • Full-text search engine
  • Table, Index, Memo, and communication encryption
  • Compatible with native TDataset components
  • Online Backup
  • Server supports Replication

For more information, see the Advantage Database Server website.

See also