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What are the several kinds of the update operations on relations? Also explain the constraints on these update operation. Give instance in support of your answer.
There are three primary update separation on relations: (i) Insert : It is used to insert a latest tuple or tuples in a relation. Insert can violate any of the four tuples of constraints: Domain constraints, key constraints, entity integrity and referential integrity (ii) Delete : It is used to delete tuples. The delete operation can violate just referential integrity, if the tuple being deleted is referenced through the foreign keys from other tuples in the database (iii) Modify: It is used to change value of a few attributes in existing tuples. Modify can also violate any of the four constraints as specified within insert operation.
Examples: (1) Inserting a tuple having null value for primary key violates entity integrity (2) Deleting a tuple in a table for that tuples exist other tables that are dependent on those tuples will violate referential key integrity. (3) Modifying a primary key attribute to any other such that is aheady exists in the table will violate entity integrity.
Mention the several levels in security measures. A) Database system B) Operating system C) Network D) Physical Human
Question 1 Create a table student with attributes student name, roll number, total marks and percentage. Do the following operations Insert details in to the table Update
Write a query that display ename annual salary and comm from emp table
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Submit SQL INSERT Statements that will populate the database with sample data. You must insert at least 5 records into each table in your database.Submit your SQL INSERT Statement
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For every multivalued attribute 'A', we make a new relation R that contains an attribute corresponding to plus the primary key attribute k of the relation that shows the entity typ
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