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

Explain mechanism of nested queries, Explain mechanism of nested queries? ...

Explain mechanism of nested queries? SQL gives a mechanism for nesting subqueries. A subquery is a select from where expression that is nested within one more query. A common u

What are axioms, What are axioms? Axioms or rules of inference give a s...

What are axioms? Axioms or rules of inference give a simpler technique for reasoning about

Explain how the law ensures data protection and security, Question 1: (...

Question 1: (a) Explain the legal meaning of :- (i) Computer Service Person (ii) Data holding (b) Explain how the law ensures Data protection and Security. Qu

Explain dbms- ddl-domain-alias, Briefly explain each of the following datab...

Briefly explain each of the following database terms. Use no more than 2-3 lines for each term. 1. DBMS 2. Update Anomaly 3. Alias (referring to tables in SQL queries)

Briefly describe concurrency execution, Briefly describe concurrency execut...

Briefly describe concurrency execution? Lock - based protocols Locks There are several modes in which a data item may be locked in this section we restrict our attention

Give the general form of sql query, Give the general form of SQL query? ...

Give the general form of SQL query? Select  A1, A2............., An From  R1, R2..............., Rm Where  P

What are the advantages of object id, What are the advantages of object ID?...

What are the advantages of object ID? The main advantages of Object IDs are as below: i) IDs are not changing  ii) IDs are completely independent of the changes in data v

Explain the term high level dml, Explain the term High level DML? High...

Explain the term High level DML? High level DML A high-level or non-procedural DML permit the user to specify what data is needed without specifying how it is to be acquired.

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