Referential integrity

Referential integrity

Referential integrity in a relational database is consistency between coupled tables. Referential integrity is usually enforced by the combination of a primary key or candidate key (alternate key) and a foreign key. For referential integrity to hold, any field in a table that is declared a foreign key can contain only values from a parent table's primary key or a candidate key. For instance, deleting a record that contains a value referred to by a foreign key in another table would break referential integrity. The relational database management system (RDBMS) enforces referential integrity, normally either by deleting the foreign key rows as well to maintain integrity, or by returning an error and not performing the delete. Which method is used would be determined by the referential integrity constraint, as defined in the data dictionary.

ee also

* Entity integrity
* Propagation constraint
* Dangling pointer
* Domain/key normal form


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • Referential integrity — …   Википедия

  • referential integrity — noun The property of a relational database that enforces valid relationships between tables, such that no foreign key can contain a value that does not match a primary key in the corresponding table …   Wiktionary

  • Declarative Referential Integrity — (DRI) is one of the techniques in the SQL database programming language to ensure data integrity. Contents 1 Meaning in SQL 2 Product specific meaning 3 References 4 …   Wikipedia

  • Integrity constraints — are used to ensure accuracy and consistency of data in a relational database. Data integrity is handled in a relational database through the concept of referential integrity. There are many types of integrity constraints that play a role in… …   Wikipedia

  • Data integrity — in its broadest meaning refers to the trustworthiness of system resources over their entire life cycle. In more analytic terms, it is the representational faithfulness of information to the true state of the object that the information represents …   Wikipedia

  • Entity integrity — In the relational data model, entity integrity is one of the three inherent integrity rules. Entity integrity is an integrity rule which states that every table must have a primary key and that the column or columns chosen to be the primary key… …   Wikipedia

  • Database integrity — ensures that data entered into the database is accurate, valid, and consistent. Any applicable integrity constraints and data validation rules must be satisfied before permitting a change to the database. Three basic types of database integrity… …   Wikipedia

  • Microsoft Jet Database Engine — This article is about JET Red used in Microsoft Access. For the JET Blue ISAM implementation, see Extensible Storage Engine. The Microsoft Jet Database Engine is a database engine on which several Microsoft products have been built. A database… …   Wikipedia

  • Entity-attribute-value model — (EAV), also known as object attribute value model and open schema is a data model that is used in circumstances where the number of attributes (properties, parameters) that can be used to describe a thing (an entity or object ) is potentially… …   Wikipedia

  • Data Definition Language — A data definition language or data description language (DDL) is a syntax similar to a computer programming language for defining data structures, especially database schemas. Contents 1 History 2 SQL 2.1 CREATE statements …   Wikipedia

Share the article and excerpts

Direct link
… Do a right-click on the link above
and select “Copy Link”