SQL Guide : Database system tables and system views : System views : COLUMNS
  
COLUMNS
The COLUMNS system view identifies the columns which are accessible to the current user.
Column name
Data type
Description
TABLE_CATALOG
WVARCHAR
The name of the catalog containing TABLE_NAME.
TABLE_SCHEMA
WVARCHAR
The name of the schema containing TABLE_NAME.
TABLE_NAME
WVARCHAR
The name of the table or view.
COLUMN_NAME
WVARCHAR
The name of the column of the specified table or view.
DATA_TYPE
WVARCHAR
The data type of the column.
SQL_DATA_TYPE_NUM
SMALLINT
ODBC compliant data type number.
CHAR_MAX_LENGTH
INTEGER
Maximum length for a character data type column; for others NULL.
NUMERIC_PRECISION
INTEGER
The number of digits of mantissa precision of the column, if DATA_TYPE is approximate numeric data type, NUMERIC_PREC_RADIX indicates the units of measurement; for other numeric types contains the total number of decimal digits allowed in the column; for character data types NULL.
NUMERIC_PREC_RADIX
SMALLINT
The radix of numeric precision if DATA_TYPE is one of the approximate numeric data types; otherwise NULL.
NUMERIC_SCALE
SMALLINT
Total number of significant digits to the right of the decimal point; for INTEGER and SMALLINT 0; for others NULL.
NULLABLE
CHAR
If column is known to be not nullable “NO”; otherwise “YES”.
NULLABLE_ODBC
SMALLINT
ODBC, if column is known to be not nullable 0; otherwise, 1.
REMARKS
LONG WVARCHAR
Reserved for future use.
See also
System views