PostgreSQL(Alternations)

-ALTER TABLE → modify existing table structure. -Operations: add/drop column, change datatype, rename column/table, add/drop constraints. Common ALTER TABLE Operations 1. Add a new column ALTER TABLE Employee ADD COLUMN email VARCHAR(100); 2. Drop (remove) a column ALTER TABLE Employee DROP COLUMN email; 3. Change datatype of a column ALTER TABLE Employee ALTER COLUMN salary TYPE NUMERIC(12,2); 4. Rename a column ALTER TABLE Employee RENAME COLUMN name TO full_name; 5. Add a constraint ALTER TABLE Employee ADD CONSTRAINT salary_positive CHECK (salary > 0); 6. Drop a constraint ALTER TABLE Employee DROP CONSTRAINT salary_positive; 7. Rename the table itself ALTER TABLE Employee RENAME TO Staff; This is the basic PostgreSQL... See you soon in the next blog!....