PostgreSQL Create Schema

In this section, we are going to learn how to create a schema and create a table in schema commands in pgAdmin 4 and SQL shell(psql).

In PostgreSQL, the Schema is a namespace which provides various objects such as data types, indexes, tables, operators, views, sequence, and functions. And the create statement provides the exact object name, which helps us create the object in the existing schema.

Creating Schema in PostgreSQL

The CREATE SCHEMA statement is used to create a new schema into the existing database. This statement can contain subcommands for creating objects in the new schema. And the schema name should be different from the name of any current schema in the existing database.

In PostgreSQL, we can create the schema in two different ways:

  • Create schema in pgAdmin 4
  • Create schema in psql

Note: The CREATE SCHEMA command is used to create a schema, and it cannot be nested.

The syntax for creating a schema

We have the following parameters which are used in the above syntax:

ParametersDescription
Create SchemaCreate schema is a keyword, which is used to create a new schema in the database.
Schema_NameThis parameter is used to describe the name of the schema, and the schema name should be exclusive in the existing database.
If not existsThis is an optional parameter, and it is used to create a new schema only if it does not occur.
Or
If we are trying to create a new schema without using the IF NOT EXISTS option, which is already present, it will produce an error.

Note: To implement the create schema command, we should have the CREATE privileges in the existing database.

Creating Schema in pgAdmin 4 [Graphical user interface]

In this, we are going to create a schema in the latest version of pgAdmin. We need to follow the below steps to create a schema:

Step1

  • Firstly, open pgAdmin in our local system and connect PostgreSQL to the localhost server.
PostgreSQL Create Schema

Step2

  • After that, we will expand the databases by clicking on the down-arrow icon, as shown in the below screenshot:
PostgreSQL Create Schema
  • In the above image, we can see that there are two databases available in PostgreSQL. And here, we are taking the first database, which is javatpoint.

Step3

  • Now, we will expand the database javatpoint.
PostgreSQL Create Schema

Step4

  • Once we expand the javatpoint database, we can see the Schemas.
  • After that, for creating a schema, we will right-click on the Schemas option, and then select Create, and then click on schema option from the list.
PostgreSQL Create Schema

Step5

  • Once we clicked on the schema, the Create-schema window will appear on the screen where we will provide all the necessary details like Name, etc., and click on the Save
PostgreSQL Create Schema

Step6

  • The myschema has been created once we clicked on the Save button, as shown in the below screenshot:
PostgreSQL Create Schema

Creating a schema in psql

  • Firstly, we will connect to the javatpoint database, and create a new schema as Jtp with the help of below command:

PostgreSQL Create Schema
  • The message CREATE SCHEMA indicates that the schema is created successfully.
  • To check whether the schema is created or not, we can execute the below command:
  • After executing the above command, we can see the list of schema in the below screenshot:
PostgreSQL Create Schema

PostgreSQL Create Table in Schema

Here we are going to create a table in the particular schema (which we created earlier in this section). In PostgreSQL, we can create a table in the schema in two different ways:

  • Create a table in pgAdmin schema
  • Create a table in psql schema

Create a table in pgAdmin schema

Once we are done creating the schema in pgAdmin, we are going to create a table in the particular schema. And for this we are going to follow the below steps:

Step1

  • Firstly, we are expanding the newly created schema myschema, and we can see the myschema contains the following:
    • Collations
    • Tables
    • Sequences
    • Functions
    • Procedure
    • Types
    • View and so on.
PostgreSQL Create Schema

Step2

  • Now, we will right-click on the Tables option under the myschema, and where we will select the Create option from the given drop-down and then click on the Table as we can see in the below image:
PostgreSQL Create Schema

Step3

  • Once we clicked on the table option, the Create-Table window will appear on the screen where we will enter all the necessary details like Table name. In our case, we will create a table called Student.
PostgreSQL Create Schema

Step4

  • After that, we will move to the Column tab in the same window then click on the + sign to add columns in a particular table.
  • And we can select the Data types from the given drop-down list as well as we can change the columns Not-null preference and also set the Primary key.
  • And then click on Save to complete the process of creating a table as we can see in the below screenshot:
PostgreSQL Create Schema
  • And we can see that the Student table is created under the Table
PostgreSQL Create Schema

Create a table in the psql schema

Now, we will create a table in the psql schema, which we created above. But first, we will see the syntax of creating a table in psql schema.

The syntax to Create Table in Schema

The general syntax, for creating a table in the schema is as follows:

The following parameters are used in the above syntax:

ParametersDescription
Create tableCreate table is a keyword, which is used to create a table in the existing schema.
Schema_nameIt is used to specify the current schema name.
Table_nameIt is used to describe the name of the table, and the table name should be unique in the existing schema.
  • The below command is used to create a table in the psql schema:

PostgreSQL Create Schema
  • The above command will create an empty table. And we can check the created table with the help of below command:

Output

The following screenshot will display the result of the above-created table:

PostgreSQL Create Schema




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