Database Constraints Introduction
Table of Content:
Database constraints are rules that are enforced on data in a database to ensure data accuracy, consistency, and integrity. They are used to ensure that data stored in a database is valid, conforms to the business rules, and is reliable. Constraints help to prevent errors, data loss, and inconsistencies in the database.
There are several types of constraints that can be applied to a database:
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Primary key constraints: This ensures that each row in a table has a unique identifier, which is used to identify a particular record.
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Foreign key constraints: This ensures that the values in one table's column match the values in another table's column, thus maintaining the referential integrity between two tables.
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Check constraints: This ensures that the data entered into a column or row meets a specific condition or set of conditions.
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Unique constraints: This ensures that no two rows in a table have the same value for a specific column or set of columns.
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Not null constraints: This ensures that a column cannot contain null or empty values.
By enforcing these constraints, a database can ensure the accuracy and consistency of its data, which is crucial for effective data management and decision-making.