Microsoft Access [ maɪ.kɹoʊ.sɒft æk.sɛs ] (abbreviated MS Access, according to Engl. Access, " access " ) is an application within the Microsoft Office family and is as individual Office application or as part of Office Professional ( Office package ) available. Access combines the Microsoft Jet Engine as a relational database management system with the tools of an integrated development environment that is suitable with their graphical user interfaces especially for the target group of end-users for the production of database applications. MS Access are supported ( with restrictions), the database programming language SQL -92. It is a proprietary software package from Microsoft.
The success of desktop database applications such as dBASE and FoxPro led Microsoft in the mid- 1980s to the decision to develop its own database application for the then new Windows operating system. The development work under the project name Omega was delayed again and again until the early 1990s that still buggy version 1.0, and shortly thereafter the stable version 1.1 came on the market.
The current version is Access 2013. Unlike the other Office programs Word, Excel and PowerPoint, which are also offered for the operating system Mac OS X from Apple, Access is only available for Windows.
By default, Access stores all data in a database application into a single file of your own mdb file format. This includes both the surface elements, and the database tables. Alternatively it is very easy to drive the data ( table definitions and the database ), in contrast to the surface ( and other Visual Basic modules, macros, reports, etc.) to keep them in different files ( front and back ). When including or linking to external data sources (tables) different versions of Access, but also access foreign formats such as dBASE, as well as many popular data sources can be accessed eg via ODBC.
Unlike previous PC-based database systems MS Access supports a relational database model with referential integrity checks. To access external Access databases, is best suited which also developed by Microsoft ODBC API. It can also be accessed Access databases from other programming languages , such as Delphi, Visual Basic, etc. through the use of ADO, or the slightly older, but tailored to MDBs DAO. To merely integrate this format, Access needs to be neither licensed nor installed. In Windows 2000 ADO MDAC as part of a part of the operating system. For earlier versions of Windows, it can be installed free of charge.
MS Access, is based on the Microsoft Jet Engine as a database backend, is well suited for small to medium sized databases at ( approximately ) up to ten simultaneous users,. In addition, Microsoft recommends that rather simple migration to MS SQL server. In order to simplify the multi-user access within the MDB file format, write accesses done in older versions of Access MDB database always at the end of file. Deleted or modified elements remain as " holes" in the file are available until the Access file is compressed (in the narrow sense, it is a defragment the database file itself). In newer versions of a regular compression is no longer necessary. By gradually expanded, including cache - based access techniques, it was possible from version 1.0 to achieve considerable access speeds, even in networks.
The operation of access applications on the LAN is bound to a stable network environment. Even small interruptions can tear down the connection to the backend. Access remains mostly stable, only the affected users must restart their database application again. With stable hardware and network reorganization (Repair and compression) of the database is required only in rare cases. Access is stable with its MDB format compared to other file-based databases, although classical SQL Server usually are of course far more stable. In practice, in standard established networks, such as Ethernet-based, expect no problems. For use in heterogeneous networks or WiFi access, however, is - as all file-based ( status-related ) access procedures that take place concurrently on the file system - less suitable here should database server ( DB2 Server, MS SQL Server, MySql server, etc. ) are preferred.
To overcome these weaknesses, the database access from MS Access since the first versions based on a SQL engine, which allows for easy migration to an SQL server. These Access was from the 2000 version extended so that applications can be on a database that runs on a Microsoft SQL Server, constructed directly, instead of involving them through ODBC. A new file format with the extension adp has been developed for this purpose and the file access DAO (Data Access Objects) to the more versatile ADO ( Active Data Objects ) is inverted. ADO abstracted much more of the database sources used than its predecessor and therefore has a higher access speed.
With Access a free desktop version of Microsoft SQL Server is shipped from the 2000 version, that can be managed directly through the Access interface. Therefore, it is not necessary to purchase an additional license program. However, the management capabilities of SQL Server-based functions (eg permissions ) compared to the full version is very limited, which is why the use of MSSQL server is useful for larger projects. Since SQL Server 2005, but this is only true to a limited extent, since with this version of the Management Studio Express is included in the price for free.
By providing visual programming objects that are optimized in terms of database access, it is possible to use Access to create database-driven applications within a short time ( rapid prototyping), without extensive programming work ( such as those in C or C are necessary) having to perform. It is possible to rely on scripts that were created in a special macro language. In order to create complex applications, a development environment for Visual Basic for Applications (VBA ) is built into Access. To improve the speed of the program execution, the source code created on the basis of VBA can compiled and referred to as an optimized program code, also called " P- code" (derived from " pseudo-code ", but here different meaning ) in the database file ( the same as in the *. MDE ) are stored.
For the dissemination of developed databases to users who do not have access, there is the runtime versions. These are created with the Office Developer Edition, which is free or paid depending on the version of Access.
To create a database of several object types are created by the developer:
- Tables for storing the data
- Queries for processing (filtering, sorting, etc. ) of the data
- Forms for data input via screen mask
- Reports to output the data to the screen or to a printer
- Macros for easy automation
- Visual Basic modules for programming in Visual Basic for Applications (VBA )
- Access 2: " Access Developer 's Toolkit " ( ADT) for Access2
- Access 95: " Access Developer 's Toolkit " ( ADT) for Access95
- Access 97: " Office Developer 's Edition " ( ODE)
- Access 2000: "Microsoft Office Developer " (MOD )
- Access XP: " Office XP Developer "
- Access 2003: " Access 2003 Developer Extensions "
- Access 2007
- Access 2010
- Access 2013