References
SQL Reference
SQL Statements
Alter Table

Reference: Alter Table Statement

Alter table allows modifying the definition of a table. See PostgreSQL: ALTER TABLE for the PostgreSQL documentation.

Column statememts

RENAME COLUMN 

ALTER TABLE IF EXISTS movies RENAME COLUMN runlength TO duration;

Rename column of table with table_name and current_column_name to the new_column_name. If exists checks if the table exists and only tries to rename in the case of existence.

Constraint statements

ADD CONSTRAINT

Adds a constraint to an existing table. CedarDB supports named primary key, foreign key, and unique constraints:

ALTER TABLE orders ADD CONSTRAINT orders_pk primary key (id);
ALTER TABLE orders ADD CONSTRAINT orders_customer_fk foreign key (customer) references customers (id);
ALTER TABLE orders ADD CONSTRAINT orders_unique unique (customer, item);

The CONSTRAINT <name> part can be omitted entirely, in which case CedarDB automatically assigns a default name using the same conventions as PostgreSQL:

  • Primary key: tablename_pkey
  • Unique: tablename_colname_key
  • Foreign key: tablename_colname_fkey

DROP CONSTRAINT

Removes a constraint by name, using either an explicit name or the default name:

ALTER TABLE orders DROP CONSTRAINT orders_unique;
ALTER TABLE orders DROP CONSTRAINT orders_pkey;
Alter RoleAnalyze