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Explain the two constraints, check and foreign key in SQL along with an example for each. Give the syntax.
CHECK constraint - CHECK constraint specifies an expression which must always be true for every row in the table. It can't refer to values within other rows.Syntax:ALTER TABLE ADD CONSTRAINT CHECK();
FOREIGN KEY constraint - A foreign key is a combination of columns along with values based on the primary key values from another table. A foreign key constraint, also called as referential integrity constraint, specifies in which the values of the foreign key correspond to actual values of the primary or unique key in other table. One can refer to a primary or unique key in the similar table also.
Syntax: ALTER TABLE ADD CONSTRAINT FOREIGN KEY()REFERENCES () ON {DELETE | UPDATE}CASCADE;
A relation instance indicates as r is a collection of tuples for a given relational schema at a exact point of time. A relation state r of the relation schema R (A 1 ,A 2 ,.....
Define about the Stored Procedure - It's a set of T-SQL statements combined together to perform a single task formed by combining numerous small tasks. - When you essentiall
Physical Database Design Issues The database design includes the process of logical design with the use of E-R diagram, normalisation, etc., followed by the physical design.
Which types of data supported by MySQL for Time and Date formats? MySQL supports a number of time and date column formats: Some of them are 1) DATE 2) DATETIME 3) TIM
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Which two files are used during operation of the DBMS? Data dictionary and transaction log are two files used during operation of the DBMS.
Create an entity relationship diagram, Database Management System
Northwind Pty Ltd sells a variety of food products throughout the world. They want to use the reporting features of SAP''s Business Information Warehouse to better understand thei
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