---
title: "Data Types"
id: infoschema-datatypes
pg_version: "20devel"
---

<a id="infoschema-datatypes"></a>

## 35.2. 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: **`cardinal_number`**

 A nonnegative integer. **`character_data`**

 A character string (without specific maximum length). **`sql_identifier`**

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

 A domain over the type `timestamp with time zone` **`yes_or_no`**

 A character string domain that contains either `YES` or `NO`. This is used to represent Boolean (true/false) data in the information schema. (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.)  Every column in the information schema has one of these five types.