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Describe integrity constraints?
Integrity Constraints - A database is just as excellent as the information stored in it, and a DBMS must therefore help avoid the entry of incorrect information. An integrity constraint is a condition specified on a database schema and restricts the data that can be stored in an instance of the database. If a database instance satisfies all the integrity constraints specified on the database schema, it is a legal instance. A DBMS enforces integrity constraints, in that it permits only legal instances to be stored within the database.
Integrity constraints are specified and enforced at various times:
When the DBA or end user describes a database schema, he or she specifies the integrity constraints which must carry on any instance of this database. While a database application is run, the DBMS checks for violations and disallows changes to the data in which violate the specified integrity constraints. Several types of integrity constraints can be specified in the relational model, such as, Not Null, Check, Unique, Primary Key, etc.
Deletion Anomalies: Loss of important Information: In some cases, useful information may be lost when a tuple is deleted. For instance, if we delete the tuple corresponding to stu
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Describe Parameteric end users? Parametric end users might be given update access, but are commonly not permitted to change the structure of data.
What is schema
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