Update command- sql, PL-SQL Programming

Assignment Help:

UPDATE Command- SQL

Loosely speaking, UPDATE changes some of the column values of some existing rows of its target table. Thus, although some rows disappear from the target and others arrive in it, so to speak, the cardinality of the table does not change. Suppose the exam board for course C2 decides that the exam has been marked too harshly and everybody's mark is to be increased by 5. Example shows how.

Example: Adding 5 to all the marks for course C2

UPDATE EXAM_MARK SET Mark = Mark + 5

WHERE CourseId = 'C2';

The syntax is self-explanatory. The WHERE specification is optional and defaults to WHERE TRUE, meaning that the specified changes are to be applied to all existing rows in the target table. The expression Mark = Mark + 5 is a column assignment. When several column assignments are needed they are separated by commas and the semantics of multiple assignment as described in the theory book apply: the right-hand sides are all evaluated before any column assignments are performed. The same column cannot be the target or more than one assignment.


Related Discussions:- Update command- sql

Parameter and keyword description - %type attribute, Parameter and Keyword ...

Parameter and Keyword Description: collection_name: This keyword identifies the index-by table, nested table, or varray formerly declared within the present scope. cu

Example of shorthand for a row constraint - sql, Example of Shorthand for a...

Example of Shorthand for a row constraint Example: Shorthand for a row constraint ALTER TABLE EXAM_MARK ADD CONSTRAINT Mark_in_range CHECK (Mark BETWEEN 0 AND 100);

Develop data business intelligence project, Develop Data Business Intellige...

Develop Data Business Intelligence Project Project Description: We are linking our Microsoft SQL Database to GoodData Business Intelligence. We are seeking somebody who has e

Aggregate assignment-declarations in sql, Aggregate Assignment The %ROWT...

Aggregate Assignment The %ROWTYPE declaration cannot include an initialization clause. Though, there are two ways to assign values to all fields in a record at once. At First, t

Using prior and next - collection method, Using PRIOR and NEXT The PRI...

Using PRIOR and NEXT The PRIOR(n) returns the index number that precede index n in a collection. The NEXT(n) returns the index number which succeed the index n. If n has no pr

Multiset types - sql, Multiset types - SQL An SQL multiset is what in ...

Multiset types - SQL An SQL multiset is what in mathematics is also known as a bag-something like a set except that the same element can appear more than once. The body of an

Components of an object type - attributes in pl/sql, Attributes: Just ...

Attributes: Just similar to variable, an attribute is declared with a name and datatype. The name should be exclusive within the object type. The datatype can be any Oracle ty

Creating and destroying base tables, Creating and Destroying Base Tables: ...

Creating and Destroying Base Tables: Example shows an SQL command to create the base table counterpart of the ENROLMENT variable Example  Creating a base table. CREATE T

Parameter modes, Parameter Modes   To define the behavior of formal pa...

Parameter Modes   To define the behavior of formal parameters you use the parameter modes. The 3 parameter modes, IN, OUT, & IN OUT, can be used with any subprogram. Though, a

Use the returning clause -improve performance of application, Use the RETUR...

Use the RETURNING Clause Frequently, the application requires information about the row affected by a SQL operation, for illustration, to produce a report or take a subsequent

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd