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

Declaring subprograms, Declaring Subprograms   You can declare subprog...

Declaring Subprograms   You can declare subprograms in any PL/SQL subprogram, block, or package. But, you should declare subprograms at the end of the declarative part after a

Explicit cursor attributes, Explicit Cursor Attributes The cursor varia...

Explicit Cursor Attributes The cursor variable or each cursor has four attributes: %FOUND, %ISOPEN, %ROWCOUNT, and %NOTFOUND. When appended to the cursor or cursor variable, th

Remote operations in pl sql, Remote Operations: As the illustration sh...

Remote Operations: As the illustration shows below, the PL/SQL subprograms can execute the dynamic SQL statements which refer to the objects on a remote database: PROCEDURE

Order of evaluation-pl/sql expressions , Order of Evaluation When you do...

Order of Evaluation When you do not use the parentheses to specify the order of evaluation, the operator precedence determine the order. Now compare the expressions below: NOT

Ensuring backward compatibility, Ensuring Backward Compatibility   The...

Ensuring Backward Compatibility   The PL/SQL Version 2 permits some abnormal behavior which Version 8 disallows. Particularly, Version 2 permits you to (i) Make the forw

Tautologies, Tautologies: Above given table allows us to read the trut...

Tautologies: Above given table allows us to read the truth of the connectives in the next manner. Just expect we are looking at row three. It means this says that, if there P

Triffic light control system, write the program for traffic control system ...

write the program for traffic control system with 10 second, 15 secod, and 20 second delay

Sql outer join, SQL outer join SELECT * FROM IS_CALLED NATURAL LEFT...

SQL outer join SELECT * FROM IS_CALLED NATURAL LEFT JOIN IS_ENROLLED_ON Note that adding LEFT to an invocation of CROSS JOIN has no effect unless the right-hand operand

Example of coalesce operator - sql, Example of COALESCE operator Examp...

Example of COALESCE operator Example: Give the total of marks for each exam (simplified solution) SELECT CourseId, COALESCE ((SELECT SUM (Mark) FROM EXAM_MARK AS EM

Write a stored procedure, a. Create a table odetails_new. It has all the a...

a. Create a table odetails_new. It has all the attributes of odetails and an additional column called cost, whose values are the product of the quantity and price of the part bein

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