How is the role of the primary key identification tuple implemented in a relational database?

The role of the primary key identification tuple in the relational database is realized through entity integrity rules.

Entity integrity rules ensure that there are no identical tuples in the relationship. This is achieved by setting the primary key in the relational database.

Extended information:

Relational database:

is a database based on the relational database model, using concepts and methods such as set algebra to Processing data in a database is also organized into a set of formally descriptive tables. The essence of this form of table is to load a special collection of data items. The data in these tables can be stored in many different ways. Fetch or reconvene without reorganizing the database tables. A relational database definition results in a table of metadata or a formal description of tables, columns, ranges, and constraints. Each table (sometimes called a relationship) contains one or more data types represented by columns. Each row contains a unique data entity of the type defined by the column. When creating a relational database, you can define the range of possible values ​​for a data column and further constraints that may apply to that data value. The SQL language is a standard user and application interface to a relational database. The advantage is that it is easy to expand, and after the initial database creation, a new data type can be added without modifying all existing applications. Mainstream relational databases include oracle, db2, sqlserver, sybase, mysql, etc.

Entity integrity rules:

This rule requires that the tuples in the relationship cannot have null values ​​in the attributes that make up the primary key. If a null value appears, then the primary key value cannot be uniquely identified. The role of tuples.

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