What are the different types of constraints that can be defined in Oracle?

Types of Constraints in Oracle Database

There are several types of constraints that can be defined in Oracle Database. These constraints help in maintaining the integrity and consistency of the data within the database tables. The main types of constraints in Oracle include:

• Primary Key Constraint: A primary key constraint ensures that each row in a table is unique and not null. It is used to uniquely identify each record in a table.
• Foreign Key Constraint: A foreign key constraint establishes a relationship between two tables by linking a column from one table to a column in another table. It ensures referential integrity between the tables.
• Unique Constraint: A unique constraint ensures that all values in a column or a set of columns are unique, except for null values. It prevents duplicate values from being entered in the table.
• Check Constraint: A check constraint enforces a condition on a column to ensure that the data entered meets a specific criteria. It can be used to limit the range of values that can be stored in a column.
• Not Null Constraint: A not null constraint ensures that a column cannot contain null values. It makes it mandatory for a column to have a value for each row.

By defining these constraints in Oracle Database, you can maintain data integrity and ensure the accuracy and reliability of your database records.