CodePudding user response:

Entity integrity rules, referential integrity rules, the integrity of the user to define rules,

CodePudding user response:

Entity integrity rules, referential integrity rules, the integrity of user defined rules.

CodePudding user response:

The integrity of the relationship between the main including domain integrity, entity integrity and referential integrity,
1. Domain integrity
Domain integrity constraints on attributes of the data fields in the table, it includes the range of values of the fields, field types and effective rules such as constraints, it is defined by determining the relational structure of field attributes decision,
2. Entity integrity
Entity integrity is the record and uniqueness in the relationship, which is the primary key constraint, accurately, entity integrity refers to the relationship between the primary attribute value cannot be Null and cannot have the same values,
3. Referential integrity
Referential integrity is to establish a relationship between the data table in a relational database data referring to the constraints of reference, also is the foreign key constraints, accurately, referential integrity refers to the relationship between a foreign key in another relationship must be the primary key of the effective value, or NULL