2.2.5.5.4 sql_variant Values
The SSVARIANTTYPE is a special data type that acts as a place holder for other data types. When a SSVARIANTTYPE is filled with a data value, it takes on properties of the base data type that represents the data value. To support this dynamic change, for those that are not NULL (GEN_NULL) the SSVARIANTTYPE instance has an SSVARIANT_INSTANCE internal structure according to the following definition.
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VARIANT_BASETYPE = BYTE ; data type definition VARIANT_PROPBYTES = BYTE ; see below VARIANT_PROPERTIES = *BYTE ; see below VARIANT_DATAVAL = 1*BYTE ; actual data value SSVARIANT_INSTANCE = VARIANT_BASETYPE VARIANT_PROPBYTES VARIANT_PROPERTIES VARIANT_DATAVAL
VARIANT_BASETYPE is the TDS token of the base type.
|
VARIANT_BASETYPE |
VARIANT_PROPBYTES |
VARIANT_PROPERTIES |
|---|---|---|
|
GUIDTYPE, BITTYPE, INT1TYPE, INT2TYPE, INT4TYPE, INT8TYPE, DATETIMETYPE, DATETIM4TYPE, FLT4TYPE, FLT8TYPE, MONEYTYPE, MONEY4TYPE, DATENTYPE |
0 |
<not specified> |
|
TIMENTYPE, DATETIME2NTYPE, DATETIMEOFFSETNTYPE |
1 |
1 byte specifying scale |
|
BIGVARBINARYTYPE, BIGBINARYTYPE |
2 |
2 bytes specifying max length |
|
NUMERICNTYPE, DECIMALNTYPE |
2 |
1 byte for precision followed by 1 byte for scale |
|
BIGVARCHARTYPE, BIGCHARTYPE, NVARCHARTYPE, NCHARTYPE |
7 |
5-byte COLLATION, followed by a 2-byte max length |
Note Data types cannot be NULL when inside a sql_variant. If the value is NULL, the sql_variant itself has to be NULL, but it is not allowed to specify a non-null sql_variant instance and have a NULL value wrapped inside it. A raw collation SHOULD NOT be specified within a sql_variant.<15>