Data types in sql, PL-SQL Programming

Data Types in SQL

SQL's concept does not differ significantly from that defined in the theory book, apart from that business concerning NULL. However, the theory book equates type with the term domain used in much of the relational database literature. SQL is at odds with this equation because it uses domain for a defined subset of a given type that is not itself a type. For example, the domain WEEKDAY might be defined to consist of the values 'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', and 'Saturday', but the declared type of a column defined on that domain is that on which the domain itself is defined, perhaps VARCHAR(9). Also, whereas a domain is defined by specifying a constraint (on some underlying type), a constraint cannot be used to specify a user-defined type.

Posted Date: 1/18/2013 1:55:02 AM | Location : United States







Related Discussions:- Data types in sql, Assignment Help, Ask Question on Data types in sql, Get Answer, Expert's Help, Data types in sql Discussions

Write discussion on Data types in sql
Your posts are moderated
Related Questions
Table Comparison - SQL The following definitions for relation comparisons: Let r1 and r2 be relations having the same heading. Then: r1 ⊆ r2 is true if every tuple of r1

to write a heap sort program usin pl-sql

Manipulating Collections Within PL/SQL, the collections add procedural power and flexibility. The biggest benefit is that your program can compute subscripts to process the spec

Use Object Types and Collections The Collection types and object types increase your efficiency by allowing for the realistic data modeling. The Complex real-world entities an

Closing a Cursor The CLOSE statements disable the cursor, and the result set becomes undefined. An illustration of the CLOSE statement as shown: CLOSE c1;

PRIMARY KEY: PRIMARY KEY  indicates that the table is subject to a key constraint, in this case declaring that no two rows in the table assigned to ENROLMENT can ever have the

Cursor Variables As Parameters You can declare the cursor variables as the formal parameters of the functions and procedures. In the illustration below, you define the REF CUR

Advantages of Subprograms The Subprograms give extensibility; that is, tailor the PL/SQL language to suit your requirements. For illustration, if you require a procedure which

Package Body: The package specification is implemented by the package body. That is, the package body has the definition of every cursor and the subprogram declared in the pac

Loop Labels Like the PL/SQL blocks, loops can also be labeled. The label, an undeclared identifier enclosed by double angle brackets, should appear at the beginning of the LOOP