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For referential integrity to hold in a relational database, any column in a base table that is declared a foreign key can only contain either null values or values from a parent table's primary key or a candidate key. [2] In other words, when a foreign key value is used it must reference a valid, existing primary key in the parent table.
Referential integrity Values in two relational database tables can be linked through foreign key and primary key. If values in the foreign key field are not constrained by internal mechanisms, then they should be validated to ensure that the referencing table always refers to a row in the referenced table. Spelling and grammar check
An example of a data-integrity mechanism is the parent-and-child relationship of related records. If a parent record owns one or more related child records all of the referential integrity processes are handled by the database itself, which automatically ensures the accuracy and integrity of the data so that no child record can exist without a parent (also called being orphaned) and that no ...
SQL Query Analyzer is a helpful tool when using Microsoft SQL Server. [citation needed] One commonly used function, [vague] create_input_dialog["label"], is used to validate the output with user inputs. The design of forms for automated database testing, form front-end and back-end, is helpful to database maintenance workers. Data load testing:
A list of all available firing events in Microsoft SQL Server for DDL triggers is available on Microsoft Docs. [ 2 ] Performing conditional actions in triggers (or testing data following modification) is done through accessing the temporary Inserted and Deleted tables.
SQL:2011 or ISO/IEC 9075:2011 (under the general title "Information technology – Database languages – SQL") is the seventh revision of the ISO (1987) and ANSI (1986) standard for the SQL database query language. It was formally adopted in December 2011. [1] The standard consists of 9 parts which are described in detail in SQL.
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To rephrase Zaniolo's definition more simply, the relation is in 3NF if and only if for every non-trivial functional dependency X → Y, X is a superkey or Y \ X consists of prime attributes. Zaniolo's definition gives a clear sense of the difference between 3NF and the more stringent Boyce–Codd normal form (BCNF).