ADVANCE DATABASE_assignment

Stored Procedures

A stored procedure is a subroutine available to applications accessing a relational database system.

It is actually stored in the database data dictionary.

Typical uses for stored procedures include data validation (integrated into the database) or access control mechanisms. Furthermore, stored procedures are used to consolidate and centralize logic that was originally implemented in applications. Large or complex processing that might require the execution of several SQL statements is moved into stored procedures, and all applications call the procedures only.

Cursors

A cursor is a moving placement or pointer that indicates a position. English-speakers have used the term with this meaning since the 16th century, for a wide variety of movable or mobile position-markers.

The literal meaning of the original Latin word cursor expresses the idea of someone or something that runs. Especially in the plural, Cursores 'runners', it was the name of certain functions, originally messengers. Cursor was also a Roman cognomen used by gens Papiria.

The word cursor may refer to any of the following:

• Cursor (slide rules)
• Cursor (typewriters)
• Cursor (computers)
• Cursor (databases)
• Cursor (magazine), an early computer-based "magazine" that was distributed on cassette in the late 1970s. Each issue contained programs, utilities, and games and was a forerunner of today's computer magazines that come packaged with CD-ROMs and DVD-ROMs. Cursor was produced for users of the Commodore PET.
• Cursor, a holographic sidekick character from the TV series Automan, with the ability to "draw" physical objects in real space

Embedded - SQL

Embedded SQL is a method of combining the computing power of a programming language and the database manipulation capabilities of SQL. Embedded SQL statements are SQL statements written inline with the program source code of the host language. The embedded SQL statements are parsed by an embedded SQL preprocessor and replaced by host-language calls to a code library. The output from the preprocessor is then compiled by the host compiler. This allows programmers to embed SQL statements in programs written in any number of languages such as: C/C++, COBOL and Fortran.

The ANSI SQL standards committee defined the embedded SQL standard in two steps: a formalism called Module Language was defined, then the embedded SQL standard was derived from Module Language.^[1] The SQL standard defines embedding of SQL as embedded SQL and the language in which SQL queries are embedded is referred to as the host language. A popular host language is C. The mixed C and embedded SQL is called Pro*C in Oracle and Sybase database management systems. In the PostgreSQL database management system this precompiler is called ECPG. Other embedded SQL precompilers are Pro*Ada, Pro*COBOL, Pro*FORTRAN, Pro*Pascal, and Pro*PL/I.

Trigger

In computing:

• Trigger function in event-driven programming
• Database trigger, procedural code that is automatically executed in response to certain events on a particular table in a database
• Trigger circuit, IBM's name for a flip-flop.