32.2. Data Types

The columns of the information schema views use special data types that are defined in the information schema. These are defined as simple domains over ordinary built-in types. You should not use these types for work outside the information schema, but your applications must be prepared for them if they select from the information schema.

These types are:


A nonnegative integer.


A character string (without specific maximum length).


A character string. This type is used for SQL identifiers, the type character_data is used for any other kind of text data.


A domain over the type timestamp with time zone

Every column in the information schema has one of these four types.

Boolean (true/false) data is represented in the information schema by a column of type character_data that contains either YES or NO . (The information schema was invented before the type boolean was added to the SQL standard, so this convention is necessary to keep the information schema backward compatible.)