Null substitution values

When a row containing NULL values is fetched from a server, Client-Library substitutes specified “null substitution values” for the null columns when copying the row data to program variables.

Table 3-4 lists Client-Library’s default null substitution values:

**Table 3-4: Default null substitution values**
Destination type	Null substitution value
CS_BINARY_TYPE	Empty array
CS_VARBINARY_TYPE	Empty array
CS_BIT_TYPE	0
CS_CHAR_TYPE	Empty string
CS_VARCHAR_TYPE	Empty string
CS_DATE_TYPE	4 bytes of zeros
CS_DATETIME_TYPE	8 bytes of zeros
CS_DATETIME4_TYPE	4 bytes of zeros
CS_TINYINT_TYPE	0
CS_SMALLINT_TYPE	0
CS_BIGINT_TYPE	0
CS_INT_TYPE	0
CS_UINT_TYPE	0
CS_UBIGINT_TYPE	0
CS_USMALLINT_TYPE	0
CS_DECIMAL_TYPE	0.0 (with default scale and precision)
CS_NUMERIC_TYPE	0.0 (with default scale and precision)
CS_FLOAT_TYPE	0.0
CS_REAL_TYPE	0.0
CS_MONEY_TYPE	$0.0
CS_MONEY4_TYPE	$0.0
CS_BOUNDARY_TYPE	Empty string
CS_SENSITIVITY_TYPE	Empty string
CS_TEXT_TYPE	Empty string
CS_UNITEXT_TYPE	Empty string
CS_TIME_TYPE	4 bytes of zeros
CS_XML_TYPE	Empty string
CS_IMAGE_TYPE	Empty array

To change null substitution values, an application can call the CS-Library routine cs_setnull.