Using this option requires superuser privilege. TYPMOD_IN can be set to the name of a type modifier input function, or NONE to remove the type's type modifier input function. SEND can be set to the name of a binary output function, or NONE to remove the type's binary output function. RECEIVE can be set to the name of a binary input function, or NONE to remove the type's binary input function. Specifically, these properties can be changed: It allows adjustment of a subset of the base-type properties that can be set in CREATE TYPE.

This form is only applicable to base types. An error will occur if the specified value is not present or the new name is already present.

The value's place in the enum's ordering is not affected. This form renames a value of an enum type. Otherwise, an error will occur if the new value is already present. If IF NOT EXISTS is specified, it is not an error if the type already contains the new value: a notice is issued but no other action is taken. Otherwise, the new item is added at the end of the list of values. The new value's place in the enum's ordering can be specified as being BEFORE or AFTER one of the existing values. This form adds a new value to an enum type. This form changes the type of an attribute of a composite type. If IF EXISTS is specified and the attribute does not exist, no error is thrown. This form drops an attribute from a composite type. This form adds a new attribute to a composite type, using the same syntax as CREATE TYPE. It changes the name of an individual attribute of the type. This form is only usable with composite types. This form moves the type into another schema.

Alter column datatype in postgresql