Datatypes
Datatypes
Each value manipulated by Oracle has a datatype. A value’s datatype associates a fixed set of properties with the value. These properties cause Oracle to treat values of one datatype differently from values of another. For example, you can add values of NUMBER datatype, but not values of RAW datatype.
When you create a table or cluster, you must specify a datatype for each of its columns. When you create a procedure or stored function, you must specify a datatype for each of its arguments. These datatypes define the domain of values that each column can contain or each argument can have. For example, DATE columns cannot accept the value February 29 (except for a leap year) or the values 2 or ’SHOE’. Each value subsequently placed in a column assumes the column’s datatype. For example, if you insert ’01-JAN-98’ into a DATE column, then Oracle treats the ’01-JAN-98’ character string as a DATE value after verifying that it translates to a valid date.
Oracle provides a number of built-in datatypes as well as several categories for user-defined types that can be used as datatypes. The syntax of Oracle datatypes appears in the diagrams that follow. The text of this section is divided into the following sections:
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Oracle Built-in Datatypes
ANSI, DB2, and SQL/DS Datatypes
User-Defined Types
Oracle-Supplied Types
Note: The Oracle precompilers recognize other datatypes in embedded SQL programs. These datatypes are called external datatypes and are associated with host variables. Do not confuse built-in datatypes and user-defined types with external datatypes. For information on external datatypes, including how Oracle converts between them and built-in datatypes or user-defined types, see Pro*COBOL Precompiler Programmer’s Guide, and Pro*C/C++ Precompiler Programmer’s Guide.
2-2 Oracle9i SQL Reference
Datatypes
datatypes::=
Oracle_built_in_datatypes
ANSI_supported_datatypes
user_defined_types
Oracle_supplied_types
Oracle_built_in_datatypes::=
character_datatypes
number_datatypes
long_and_raw_datatypes
datetime_datatypes
large_object_datatypes
rowid_datatypes
character_datatypes::=
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BYTE |
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CHAR |
CHAR |
( |
size |
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) |
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BYTE |
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CHAR |
VARCHAR2 |
( |
size |
) |
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NCHAR |
( |
size |
) |
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NVARCHAR2 |
( |
size |
) |
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number_datatypes::=
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, |
scale |
( |
precision |
) |
NUMBER |
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Basic Elements of Oracle SQL 2-3
Datatypes
long_and_raw_datatypes::=
LONG
LONG 
RAW
RAW 
( 
size 
)
datetime_datatypes::=
DATE |
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LOCAL |
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( |
fractional_seconds_precision |
) |
WITH |
TIME |
ZONE |
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TIMESTAMP |
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( |
year_precision |
) |
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INTERVAL |
YEAR |
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TO |
MONTH |
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( |
day_precision |
) |
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( |
fractional_seconds_precision |
) |
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INTERVAL |
DAY |
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TO |
SECOND |
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large_object_datatypes::=
BLOB
CLOB
NCLOB
BFILE
rowid_datatypes::=
ROWID
( 
size 
)
UROWID
The ANSI-supported datatypes appear in the figure that follows. Table 2–6 on page 2-36 shows the mapping of ANSI-supported datatypes to Oracle built-in datatypes.
2-4 Oracle9i SQL Reference
Datatypes
ANSI_supported_datatypes::=
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VARYING |
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CHARACTER |
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( |
size |
) |
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CHAR |
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VARYING |
( |
size |
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NCHAR |
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VARCHAR |
( |
size |
) |
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CHARACTER |
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VARYING |
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NATIONAL |
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( |
size |
) |
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CHAR |
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NUMERIC |
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, |
scale |
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( |
precision |
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) |
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DECIMAL
DEC
INTEGER
INT
SMALLINT
( 
size 
)
FLOAT
DOUBLE 
PRECISION
REAL
Oracle_supplied_types::=
any_types
XML_types
spatial_type
media_types
Basic Elements of Oracle SQL 2-5