In the above syntax, we have used the following parameters, which we discussed in the below table: REFERENCES parent_table_name (column_name.) The below illustrations are used to define a foreign key using the CREATE TABLE command in PostgreSQL:įOREIGN KEY (column_name. We can create a foreign key in PostgreSQL with the CREATE TABLE command's help. Creating a Foreign Key using a CREATE TABLE command Now, we are discussing each one in detail.
Note: In PostgreSQL, the ALTER TABLE command is used to add or drop a primary key.
In PostgreSQL, we can create a foreign key with the help of the following commands:
ALTER TABLE ADD FOREIGN KEY POSTGRES HOW TO
How to create a Foreign key in PostgreSQL And PostgreSQL allows us to describe a foreign key using the foreign key constraint. Note: A PostgreSQL table can have various foreign keys depending on its connection with other tables. In the parent-child relationship, the parent table keep the initial column values, and the child table's column values reference the parent column values. In other words, we can say that a foreign key makes it possible to generate a parent-child relationship with the tables. PostgreSQL foreign key constraint specifies the values in a group of columns or a column in the Child table, equivalent to the values in a group of columns or a column of the Parent table. In PostgreSQL, the foreign key's values is parallel to the actual values of the primary key in the other table that's why it is also known as Referential integrity Constraint.
The foreign key is also known as the referencing key, and it matches the primary key field from another table, which implies that the foreign key field in one table refers to the other table's primary key field. It is used to have the value in one column or group of columns displayed in the same column or combination of columns in another table. What is PostgreSQL Foreign key / Foreign Key Constraint?Ī foreign key is a group of columns with values dependent on the primary key benefits from another table. 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.
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