MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
The PARAMETERS table provides
information about parameters for stored routines (stored
procedures and stored functions), and about return values for
stored functions. The PARAMETERS
table does not include built-in (native) functions or loadable
functions. Parameter information is similar to the contents of the
param_list column in the
mysql.proc table.
The PARAMETERS table has these
columns:
SPECIFIC_CATALOG
The name of the catalog to which the routine containing the
parameter belongs. This value is always
def.
SPECIFIC_SCHEMA
The name of the schema (database) to which the routine containing the parameter belongs.
SPECIFIC_NAME
The name of the routine containing the parameter.
ORDINAL_POSITION
For successive parameters of a stored procedure or function,
the ORDINAL_POSITION values are 1, 2, 3,
and so forth. For a stored function, there is also a row that
applies to the function return value (as described by the
RETURNS clause). The return value is not a
true parameter, so the row that describes it has these unique
characteristics:
The ORDINAL_POSITION value is 0.
The PARAMETER_NAME and
PARAMETER_MODE values are
NULL because the return value has no
name and the mode does not apply.
PARAMETER_MODE
The mode of the parameter. This value is one of
IN, OUT, or
INOUT. For a stored function return value,
this value is NULL.
PARAMETER_NAME
The name of the parameter. For a stored function return value,
this value is NULL.
DATA_TYPE
The parameter data type.
The DATA_TYPE value is the type name only
with no other information. The
DTD_IDENTIFIER value contains the type name
and possibly other information such as the precision or
length.
CHARACTER_MAXIMUM_LENGTH
For string parameters, the maximum length in characters.
CHARACTER_OCTET_LENGTH
For string parameters, the maximum length in bytes.
NUMERIC_PRECISION
For numeric parameters, the numeric precision.
NUMERIC_SCALE
For numeric parameters, the numeric scale.
DATETIME_PRECISION
For temporal parameters, the fractional seconds precision.
CHARACTER_SET_NAME
For character string parameters, the character set name.
COLLATION_NAME
For character string parameters, the collation name.
DTD_IDENTIFIER
The parameter data type.
The DATA_TYPE value is the type name only
with no other information. The
DTD_IDENTIFIER value contains the type name
and possibly other information such as the precision or
length.
ROUTINE_TYPE
PROCEDURE for stored procedures,
FUNCTION for stored functions.