Data types

DB2® supports both IBM®-supplied data types (built-in data types) and user-defined data types (distinct types).

The smallest unit of data that can be manipulated in SQL is called a value. How values are interpreted depends on the data type of their source. The sources of values are:

Columns
Constants
Expressions
Functions
Special registers
Variables (such as host variables, SQL variables, parameter markers, and parameters of routines)

The following topics describes the built-in data types and distinct types.

Figure 1 shows the built-in data types that DB2 supports.

Start of change — Figure 1. Built-in data types supported by DB2

Begin figure description. A hierarchical diagram shows the relationship between the general data types and the specific data types that are contained in each general category. End figure description. — Figure 1. Built-in data types supported by DB2

Nulls
All data types include the null value. Distinct from all nonnull values, the null value is a special value that denotes the absence of a (nonnull) value.
Numbers
The numeric data types are categorized as exact numerics: binary integer and decimal; decimal floating point; and approximate numerics: floating-point
Character strings
A character string is a sequence of bytes. The length of the string is the number of bytes in the sequence. If the length is zero, the value is called the empty string. The empty string should not be confused with the null value.
Graphic strings
A graphic string is a sequence of double-byte characters.
Binary strings
A binary string is a sequence of bytes.
Large objects (LOBs)
The term large object (LOB) refers to any of the following data types: CLOB, DBCLOB, or BLOB.
Datetime values
Datetime values are neither strings nor numbers. Nevertheless, datetime values can be used in certain arithmetic and string operations and are compatible with certain strings.
Row ID values
A row ID is a value that uniquely identifies a row in a table. A column or a host variable can have a row ID data type.
XML values
An XML value represents well-formed XML in the form of an XML document, XML content, or a sequence of XML nodes.

Parent topic: Language elements