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Important Points About SQL PRIMARY KEY

DROP PRIMARY KEY IN SQL

  • A primary key is a column or a set of columns in a table that uniquely identifies each row.
  • It ensures data integrity by preventing duplicate records and null values.
  • A primary key can be defined on a single column (simple primary key) or multiple columns (composite primary key).
  • Creating a primary key automatically creates a unique index on the key column(s), improving query performance.
  • Establishing relationships between tables using SQL primary key and foreign key improve database design, reduce data redundancy, and improve data consistency.

SQL PRIMARY KEY Constraint

SQL PRIMARY KEY constraint uniquely identifies each record in a database table.

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DROP PRIMARY KEY IN SQL

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Important Points About SQL PRIMARY KEY

A primary key is a column or a set of columns in a table that uniquely identifies each row. It ensures data integrity by preventing duplicate records and null values. A primary key can be defined on a single column (simple primary key) or multiple columns (composite primary key). Creating a primary key automatically creates a unique index on the key column(s), improving query performance. Establishing relationships between tables using SQL primary key and foreign key improve database design, reduce data redundancy, and improve data consistency....

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DROP PRIMARY KEY IN SQL