PostgreSQL – How to Drop A Schema

You can create a sequence using the CREATE SEQUENCE command in PostgreSQL database. A sequence is typically used to generate unique integer values, often for primary keys or other situations where you need a unique identifier. Here’s the basic syntax to create a sequence: CREATE SEQUENCE sequence_name [ INCREMENT increment ] [ MINVALUE min_value ]…

You can add a unique constraint to a table column using the ALTER TABLE statement. A unique constraint ensures that all values in a column are unique, meaning no two rows can have the same value in that column. Below is the syntax add a unique constraint: ALTER TABLE table_name ADD CONSTRAINT constraint_name UNIQUE (column_name);…

To drop a NOT NULL constraint from an existing column in a PostgreSQL table, you can use the ALTER TABLE statement with the ALTER COLUMN clause. Here’s the basic syntax: ALTER TABLE table_name ALTER COLUMN column_name DROP NOT NULL; where table_name is the name of the table containing the column and column_name is the name…

To list the materialized views in a PostgreSQL database, you can query the system catalog tables. Materialized views are stored as objects in the database, and you can query the catalog to retrieve information about them. Here’s a query to list all materialized views in a PostgreSQL database: SELECT schemaname, matviewname FROM pg_matviews; Above query…

To describe a table in PostgreSQL and retrieve information about its columns and data types, you can use the \d command in the psql command-line tool or execute a SQL query. Here are two common methods to describe a table: Method 1: Using \d in psql (Command-Line Tool): Open a terminal and start the psql…

You can disable a user account in PostgreSQL database by revoking their login privileges. Disabling a user prevents them from connecting to the PostgreSQL database server. Here’s the basic syntax to revoke login privileges from a user globally: ALTER USER username NOLOGIN; Where username is the name of the user you want to lock/disable. By…