Category: Constraints

In this section, we are going to understand the working of the PostgreSQL NOT NULL constraint, which is used to make sure that the values of a column are not null. Examples of the PostgreSQL NOT NULL constraint, how to declare the PostgreSQL NOT NULL constraint, and adding NOT NULL Constraint to existing columns. Before understanding the concept of PostgreSQL NOT NULL…

In this section, we are going to understand the working of the PostgreSQL Check constraint, which is used to make sure that all values in a column or a field of a table satisfy particular situations. The examples of the PostgreSQL check constraint, how to create a check constraint for new tables and existing tables. What is PostgreSQL CHECK Constraint? In PostgreSQL,…

In this section, we are going to understand the working of the PostgreSQL UNIQUE constraint, which is used to make sure that all values in a column of a table are exclusive. Examples of the PostgreSQL Unique constraint, how to create a unique constraint on multiple columns, adding a unique constraint using a unique index, and also see how to drop a unique constraint for…

In this section, we are going to understand the working of the PostgreSQL Foreign Key, the examples of PostgreSQL Foreign key, how to add the PostgreSQL Foreign key into the tables using foreign key constraints. What is PostgreSQL Foreign key / Foreign Key Constraint? A foreign key is a group of columns with values dependent on the primary key benefits from another table. It is…

In this section, we are going to understand the working of the PostgreSQL Primary Key, the examples of the PostgreSQL primary key, and how to manage PostgreSQL primary key constraints over SQL commands. And also, understand how to add an auto-incremented (SERIAL)primary key to a current table and drop a primary key. What is PostgreSQL’s Primary key? It is a field in a table…

The constraints are used to describe the rules for the data columns in a table. If there is any destruction between the constraints and the data action, the action is terminated immediately. The constraints make sure the dependability and the correctness of the data in the database. In this section, we are going to discuss…