Java Enterprise in a Nutshell, Third Edition

Data Types

Each column in a table has a particular data type associated with it. SQL-92 defines a fairly broad set of data types . Different RDBMS packages provide extensions to these basic types, for multimedia data, Java objects, and so on. Oracle’s NUMBER data type, for instance, allows database designers to specify the exact precision of integer and floating-point data types. The basic SQL-92 types are listed in Table D-1. The names in parentheses are SQL-92-specified alternates for the main type names.

Table D-1. SQL-92 data types

SQL data type	Description
INTEGER (INT)	A signed integer value. The number of bits represented is implementation-dependent.
SMALLINT	A smaller signed integer value, used when storage or memory is at a premium. Generally 8 bits but implementation-dependent.
NUMERIC	A signed fixed-precision decimal. When creating a NUMERIC, you must specify the total length of the number (including the decimal point) and the number of decimal places. NUMERIC(8, 4) allows three digits, a decimal point, and four more digits.
DECIMAL	Defined the same way as a NUMERIC but may store additional precision (more decimal places).
REAL	A single-precision floating-point value. Range and accuracy are implementation-dependent.
DOUBLE PRECISION (DOUBLE)	A double-precision floating-point value. Range and accuracy are implementation-dependent, but are equal to or better than a REAL.
BIT	A fixed number (one or more) of bits. A length specifier (BIT( n )) is optional. The default size is ...