A database is a list of items stored somewhere to make their values easy to access or retrieve. This means that a database can exist anywhere, including human or non-human memory. A computer database is a list or a group of lists created as a project. There are various ways and various types of applications used to create such a list. To make it more useful, special computer applications are formally developed to help create and manage computer databases.
Microsoft Access is an application used to create computer databases that can be used on a Microsoft Windows operating system, on a web site, or on portable medium.
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A DBMS (DataBase Management System) is software that controls the organization, storage, retrieval, security and integrity of data in a database. It accepts requests from the application and instructs the operating system to transfer the appropriate data. The major DBMS vendors are Oracle, IBM, Microsoft and Sybase
DBMSs may work with traditional programming languages (COBOL, C, etc.) or they may include their own programming language for application development.
DBMSs let information systems be changed more easily as the organization's requirements change. New categories of data can be added to the database without disruption to the existing system. Adding a field to a record does not require changing any of the programs that do not use the data in that new field.
Interactive Query
Most DBMSs provide query languages and report writers that let users interactively interrogate the database and analyze its data. This important feature gives users access to all management information as needed.
Interactive data entry/updating
Many DBMSs provide a way to interactively enter and edit data, allowing you to manage your own files and databases. However, interactive operation does not leave an audit trail and does not provide the controls necessary in a large organization. These controls must be programmed into the data entry and update programs of the application.
This is a common misconception about desktop computer DBMSs. Complex business systems can be developed, but not without programming. This is not the same as creating lists of data for your own record keeping.
Data independance
With DBMSs, the details of the data structure are not stated in each application program. The program asks the DBMS for data by field name; for example, a coded equivalent of "give me customer name and balance due" would be sent to the DBMS. Without a DBMS, the programmer must reserve space for the full structure of the record in the program. Any change in data structure requires changing all application programs.
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Microsoft Access provides its own mechanism for creating and managing a database. It provides most of the tools you need to start and complete a database project.
Microsoft Data Access Object
Microsoft Data Access Object, or DAO, is a library that ships with Microsoft Access and allows you to create, maintain, and manage databases. It also provides all means to perform all needed operations on a database.
Microsoft ActiveX Data Objects
Microsoft ActiveX Data Objects, also called ADO, is a library that was developed to allow programmers with other environments to create and manage Microsoft Access databases. To support this, it provides a driver that allows these other programming environments to "attach" their applications to a Microsoft Access database. Like Microsoft Access' own library, you can use ADO inside of Microsoft Access to fully create and manage a database but you must "import" the library into your application.
Microsoft ADOX:
Microsoft ActiveX Data Object Extensions for Data Definition Language and Security, also called ADOX, is an addition to ADO. For example, since you cannot inherently create a Microsoft Access database using ADO (that is, its objects), you would instead use ADOX.
ADO.NET
ADO.NET is the latest technique developed by Microsoft and that is part of the .NET Framework. This technology allows you to use one or more libraries of the .NET Framework and one or more of the languages of the .NET Framework to create and manage your project.
Win32 API
A library is practically never complete. To complement those cited above, you can use others. One the external libraries you can use is called Win32. It belongs to Microsoft Windows and is already installed with the operating system. Because most of its functions are written in C, they cannot be directly used in a Microsoft Access database: you must import them.
Other Libraries
Besides the above libraries, Microsoft and companies other than Microsoft regularly published other libraries you can use to perform some tasks in your Microsoft Access databases. Additionally, you can also create your own library, or ask someone else to create libraries for you, using languages such as C, C++, etc.
Where else can I find information about Microsoft Access?
We have included on our site, a list of other useful Access web sites that may assist you. The web has many great sites full of information. One of the best sources of information are the Microsoft discussion groups which has not only MS Access but Word, Excel, Powerpoint, Outlook, Security, Hardware, Certification and many many other topics. If you require any specific information please contact us at any time.
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| Access Database |
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| Attribute |
Maximum |
| Microsoft Access Database (.mdb) file size |
2 gigabytes minus the space needed for system objects. |
| Number of objects in a database |
32,768 |
| Modules (including forms and reports with the HasModule property set to True) |
1000 |
| Number of characters in an object name |
64 |
| Number of characters in a password |
14 |
| Number of characters in a user name or group name |
20 |
| Number of concurrent users (We would recommend 15 max) |
255 |
| Tables |
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| Attribute |
Maximum |
| Number of characters in a table name |
64 |
| Number of characters in a field name |
64 |
| Modules (including forms and reports with the HasModule property set to True) |
1000 |
| Number of characters in an object name |
64 |
| Number of fields in a table |
255 |
| Number of open tables |
2048; the actual number may be less because of tables opened internally by Microsoft Access |
| Table size |
2 gigabyte minus the space needed for the system objects |
| Number of characters in a Text field |
255 |
| Number of characters in a Memo field |
65,535 when entering data through the user interface;
1 gigabyte of character storage when entering data programmatically |
| Size of an OLE Object field |
1 gigabyte |
| Number of indexes in a table |
32 |
| Number of fields in an index |
10 |
| Number of characters in a validation message |
255 |
| Number of characters in a validation rule |
2048 |
| Number of characters in a field property setting |
255 |
| Number of characters in a table or field description |
255 |
| Number of characters in a record (excluding Memo and OLE Object fields) |
2000 |
| Query |
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| Attribute |
Maximum |
| Number of enforced relationships |
32 per table minus the number of indexes that are on the table for fields or combinations of fields that are not involved in relationships |
| Number of tables in a query |
32 |
| Number of fields in a recordset |
255 |
| Recordset size |
1 gigabyte |
| Sort limit |
255 characters in one or more fields |
| Number of levels of nested queries |
50 |
| Number of characters in a cell in the query design grid |
1024 |
| Number of characters for a parameter in a parameter query |
255 |
| Number of ANDs in a WHERE or HAVING clause |
99 |
| Number of characters in an SQL statement |
approximately 64,000 |
| Macro |
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| Attribute |
Maximum |
| Number of actions in a macro |
999 |
| Number of characters in a condition |
255 |
| Number of characters in a comment |
255 |
| Number of characters in an action argument |
255 |
| Access Project |
|
| Attribute |
Maximum |
| Number of objects in a Microsoft Access project (.adp) |
32,768 |
| Modules (including forms and reports with the HasModule property set to True) |
1000 |
| Number of characters in an object name |
64 |
| Number of columns in a table |
250 (Microsoft SQL Server 6.5)
1024 (Microsoft SQL Server 7.0 and 2000)
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| Form and Report |
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| Attribute |
Maximum |
| Number of characters in a label |
2,048 |
| Number of characters in a text box |
65,535 |
| Form or report width |
22 in. (55.87 cm) |
| Section height |
22 in. (55.87 cm) |
| Height of all sections plus section headers (in Design view) |
200 in. (508 cm) |
| Number of levels of nested forms or reports |
7 |
| Number of fields or expressions you can sort or group on in a report |
10 |
| Number of headers and footers in a report |
1 report header/footer; 1 page header/footer; 10 group headers/footers |
| Number of printed pages in a report |
65,536 |
| Number of controls and sections you can add over the lifetime of the form or report |
754 |
| Number of characters in an SQL statement that serves as the Recordsource or Rowsource property of a form, report, or control (both .mdb and .adp) |
32,650 |
| Macro |
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| Attribute |
Maximum |
| Number of actions in a macro |
999 |
| Number of characters in a condition |
255 |
| Number of characters in a comment |
255 |
| Number of characters in an action argument |
255 |
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