PostgreSQL CREATE TABLE

CREATE TABLE To create a new table in a PostgreSQL database, one can use the UI or can also use the PostgreSQL CREATE TABLE statement.

Syntax:

CREATE TABLE table_name (
    column_1 data_type column_constraint,
    column_2 data_type column_constraint,
    ... );

Creating a TABLE using UI:

Select the database.
To get the catalogues and schema, left-click on the box type structure associated with the selected database. You will see catalogues and schema.
To get the public, left-click on the box type structure associated with the schema.
To get the table, left-click on the box type structure associated with the public.
Right-click on the selected table to get a new table line.
Click on the new table line to create the desired table.

A new TABLE is thus created.

Creating a TABLE using the Query tool:

Select the database.
To get the catalogues and schema, left-click on the box type structure associated with the selected database. You will see catalogues and schema.
To get the public, left-click on the box type structure associated with the schema.
To get the table, left-click on the box type structure associated with the public.
Left-click on the tool on the topmost line to get the Query tool.
Click on the query tool.
Put the “CREATE Table” query here.
Click on the “Play” button.

The query will thus be executed.

Example 1: Creating a table with NULL and NOT NULL column constraint.

CREATE TABLE employment  
( id INT NOT NULL AUTO_INCREMENT,  
  state VARCHAR(100) NOT NULL,  
  rate REAL );

Explanation: Column 1: id: Name of Column 1. INT: Datatype of the Column 1 which is Integer. NOT NULL: It cannot contain null values. Column 2: state: Name of Column 2. VARCHAR: Datatype of Column 2 which also specifies a maximum limit of 100 characters in length for the “state”. NOT NULL: It cannot contain null values. Column 3: rate: Name of Column 3. REAL: Datatype of Column 3. NULL: It is NULL by default and thus can contain null values.

Example 2: Creating a table with a PRIMARY KEY column constraint.

CREATE TABLE employment  
( id INT NOT NULL AUTO_INCREMENT,  
  state VARCHAR(100) NOT NULL,  
  rate REAL,
  PRIMARY KEY(id) );

Explanation: For distinguishing a unique row in a table the Primary Key Clause is used. Here “id” is defined as the Primary Key Column, thus every field of the primary key must contain NOT NULL values.

Please follow and like us: