What Is Difference Between User Define Function And Custom Control And User Define Datatype?

A user defined function, which is abbreviated as a UDF, is defined as an extension to an SQL database server. MySQL is a common type of SQL database server. A UDF can be compiled for use in an SQL query. For instance, if it is necessary to obtain a random number for use as a primary key, and if MySQL does not support the function which enables the users to obtain a random number for use as a primary key, a new external function can be written and compiled to accomplish this task. An example of such a query could be SELECT GETRANDOMKEY.

The term custom control is defined as a control object which is not native to the application. Examples of custom control objects include ActiveX controls and Visual Basic Extension controls (which are abbreviated as VBX).

The term user defined datatype is defined as a datatype which is based on the system datatypes in Microsoft SQL Server 2000. User defined datatypes are used when it becomes necessary to store the same types of data in several tables.

A User-Defined Function, or UDF, basically is a function supplied by the client of a program or environment, in a circumstance where the normal assumption is a function assembled into the program or environment.

Where as in computer programming, a Visual Basic Extent or custom control was the component model applied in Microsoft Visual Basic versions 1.0 and 3.0. Even till today it is maintained in the 16-bit version 4.0, but was outmoded by the OCXs. VBX is also supported in certain editions of Borland Delphi. Every version of Visual Basic has come with a number of controls.

In SQL databases, a user-defined function offers a mechanism for stretching the functionality of the database server by adding up a function which can be calculated in SQL statements.