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![]() | Lexical Elements of the SQL Language | ![]() | SQL Language in 602SQL | Database Tables | ![]() |
Data type specifies the set of possible values for a table column, variable, routine parameter or a function value. These types are available in 602SQL:
type ::= character_string [language_and_charset] | binary_object | bit_string | accurate_number_type
| approximate_number_type | BOOLEAN | DATE | TIME [WITH TIME ZONE] | TIMESTAMP [WITH TIME ZONE]
| domain_identifier
character_string ::= CHAR [( length )] | CHAR VARYING ( length ) | VARCHAR ( length ) | NCHAR [( length )]
| NCHAR VARYING ( length ) | CLOB [( length )] | NCLOB [( length )]
binary_object ::= BLOB [( length )]
bit_string ::= BINARY ( length ) | VARBINARY ( length ) | BIT [( length )] | BIT VARYING ( length )
accurate_number_type ::= INTEGER | SMALLINT | TINYINT | BIGINT | DECIMAL [( precision [, decim ] )]
| NUMERIC [( precision [, decim ] )]
approximate_number_type ::= REAL | DOUBLE PRECISION | FLOAT [( precision )]
Without changing a meaning you can use INT instead of INTEGER, DEC instead of DECIMAL, CHARACTER instead of CHAR, NATIONAL CHAR or NATIONAL CHARACTER instead of NCHAR, CHAR LARGE OBJECT or CHARACTER LARGE OBJECT instead of CLOB and BINARY LARGE OBJECT instead of BLOB.
You can also use LONG VARCHAR instead of CLOB, LONG VARBINARY instead of BLOB and VARBINARY instead of BIT VARYING in order to maintain compatibility with ODBC.
Internal ("physical") data types used by a client program correspond with the SQL types, when the client sends or reads data. The following table describes the correspondence between the two type sets. The third column contains the constants used for physical types description.
SQL Type Description | Internal Representation | Designation | Number |
CHAR | one character | ATT_CHAR | 2 |
CHAR(n), CHAR VARYING(n), VARCHAR(n), for n<=4090 | string character up to length n | ATT_STRING | 7 |
NCHAR(n), NCHAR VARYING(n), for n<=2045 | Unicode character string up to length n | ATT_STRING | 7 |
CLOB, CLOB(n) | character string of unlimited length | ATT_TEXT | 20 |
NCLOB, NCLOB(n) | Unicode character string of unlimited length | ATT_TEXT | 20 |
BLOB, BLOB(n) | order of bytes | ATT_NOSPEC | 21 |
BINARY(n) for n<=4090 | order of bytes up to length n | ATT_BINARY | 10 |
BIT, BIT(1), BOOLEAN | boolean values TRUE, FALSE or UNKNOWN | ATT_BOOLEAN | 1 |
BIT(n), BIT VARYING(n) for 1<n<=8*4090 | order of (n-1) / 8 + 1 bytes | ATT_BINARY | 10 |
INTEGER | 4-byte integer number | ATT_INT32 | 4 |
SMALLINT | 2-byte integer number | ATT_INT16 | 3 |
TINYINT | 1-byte integer number | ATT_INT8 | 45 |
BIGINT | 8-byte integer number | ATT_INT64 | 46 |
DECIMAL(n, d), NUMERIC(n, d) for n <= 2 | 1-byte number with a scale d | ATT_INT8 | 45 |
DECIMAL(n, d), NUMERIC(n, d) for 2 < n <= 4 | 2-byte number with a scale d | ATT_INT16 | 3 |
DECIMAL(n, d), NUMERIC(n, d) for 4 < n <= 9 | 4-byte number with a scale d | ATT_INT32 | 4 |
DECIMAL(n, d), NUMERIC(n, d) for n > 9 | 8-byte number with a scale d | ATT_INT64 | 46 |
REAL, DOUBLE PRECISION, FLOAT, FLOAT(n) | 8-byte real number | ATT_FLOAT | 6 |
DATE | date as a 4-byte number | ATT_DATE | 11 |
TIME, TIME WITH TIME ZONE | time as a 4-byte number | ATT_TIME | 12 |
TIMESTAMP, TIMESTAMP WITH TIME ZONE | date and time as a 4-byte number | ATT_TIMESTAMP | 13 |
The NULL value belongs to each type. It's equivalent to the UNKNOWN value for BOOLEAN type, equivalent to the empty string for BLOB and string character types and equivalent to the string of zeros for binary strings. It's different from any other possible values for the other types.
Variances from Intermediate Level to the Entry Level
Variances from Intermediate to the Full Level
SQL Properties in 602SQL Defined by Implementation
Operating System Requirements
Full support for Unicode and 8-bit strings in a non-Windows coding is available only in Windows 2000 and XP. The charset support depends on the system configuration for Linux systems - ISO charsets are usually supported, Windows code pages are usually not supported.
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![]() | Lexical Elements of the SQL Language | ![]() | SQL Language in 602SQL | Database Tables | ![]() |