Define assertions in sql, Database Management System

Assignment Help:

Define Assertions in SQL

a. An assertion is a predicate that is expressing a condition we wish the database to always satisfy. 

b. Domain constraints, functional dependency and referential integrity are unique forms of assertion.

c. In which a constraint cannot be expressed in these forms, we use an assertion, for example 

  • Making sure the sum of loan amounts for each branch is less than the sum of all account balances at the branch.
  • Making sure every loan customer keeps a minimum of $1000 in an account.

Related Discussions:- Define assertions in sql

Order by clause-data manipulation language, Order by clause By usin...

Order by clause By using this rows can be sorted It is used in the last portion of select statement By default it gets ascending order DESC: is used

Super keys, A super key is an attribute or set of attributes used to recogn...

A super key is an attribute or set of attributes used to recognize the records uniquely in a relation. For instance, in the Relation PERSON defines earlier PERSON_ID is a super

Explain the static or conservative two phase locking, Explain the Static or...

Explain the Static or conservative Two Phase Locking: Static (or conservative) Two Phase Locking: In this type of scheme, all the data items are locked earlier than any opera

Why are cursors necessary in embedded sql, Why are cursors necessary in emb...

Why are cursors necessary in embedded SQL? A cursor is an object used to store the output of a query for row-by-row processing through the application programs. SQL statements

What does data dictionary is a special file contains, What does data dictio...

What does data dictionary is a special file contains ? The data dictionary is a special file contain The name of all fields in all files.The width of all fields in all files an

B+ tree, construct a B+ tree for the following set of key value (2,3,5,7,11...

construct a B+ tree for the following set of key value (2,3,5,7,11,19,23,29,31) in ascending order where the pointers that will fit in one node is as follows:A. four B. six C. eigh

Explain weak and strong entity sets, Explain weak and strong entity sets? ...

Explain weak and strong entity sets? Weak and Strong entity sets: A physically powerful entity set has a primary key. All tuples in the group are distinguishable through that k

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