Usage Notes - Advanced SQL Engine - Teradata Database

To get a string representation of a JSON attribute, do the following:

1. Call FNC_GetStructuredAttributeInfo_EON.
2. If the lob_length returned from the previous function call is 0, you can use FNC_GetStructuredAttribute to get a string representation of a JSON attribute.
3. If the lob_length is not 0, you must use FNC_GetStructuredInputLobAttribute instead of FNC_GetStructuredAttribute.

Before calling FNC_GetStructuredAttribute, you must allocate the buffer pointed to by returnValue using the C data type that maps to the underlying type of the attribute. For example, if the underlying type of the attribute is an SQL INTEGER data type, declare the buffer like this:

INTEGER value;

If the attribute is a distinct type, allocate a buffer using the C data type that the distinct type represents. For example, if the attribute is a distinct type that represents an SQL SMALLINT data type, declare the buffer like this:

SMALLINT value;

If the underlying type of the attribute is a character string, FNC_GetStructuredAttribute returns a null-terminated character string. The buffer you define must be large enough to accommodate null termination.

If the attribute is a structured type, FNC_GetStructuredAttribute returns a UDT handle. To get descriptive information on the attributes of the structured type, pass the UDT handle to FNC_GetStructuredAttributeInfo.

For information on the C data types that you can use, see C Data Types.

To guarantee that the value you pass in for the bufSize argument matches the length of the data type, use the following macros defined in the sqltypes_td.h header file:

SIZEOF_CHARACTER_LATIN_WITH_NULL(len)
SIZEOF_CHARACTER_KANJISJIS_WITH_NULL(len)
SIZEOF_CHARACTER_KANJI1_WITH_NULL(len)
SIZEOF_CHARACTER_UNICODE_WITH_NULL(len)

SIZEOF_CHARACTER_UNICODE_WITH_NULL(3)

SIZEOF_VARCHAR_LATIN_WITH_NULL(len)
SIZEOF_VARCHAR_KANJISJIS_WITH_NULL(len)
SIZEOF_VARCHAR_KANJI1_WITH_NULL(len)
SIZEOF_VARCHAR_UNICODE_WITH_NULL(len)

SIZEOF_VARCHAR_UNICODE_WITH_NULL(3)

SIZEOF_BYTE(len)
SIZEOF_VARBYTE(len)

SIZEOF_GRAPHIC(len)
SIZEOF_VARGRAPHIC(len)

SIZEOF_BYTEINT
SIZEOF_SMALLINT
SIZEOF_INTEGER
SIZEOF_BIGINT
SIZEOF_REAL
SIZEOF_DOUBLE_PRECISION
SIZEOF_FLOAT
SIZEOF_DECIMAL1
SIZEOF_DECIMAL2
SIZEOF_DECIMAL4
SIZEOF_DECIMAL8
SIZEOF_DECIMAL16
SIZEOF_NUMERIC1
SIZEOF_NUMERIC2
SIZEOF_NUMERIC4
SIZEOF_NUMERIC8
SIZEOF_NUMERIC16
SIZEOF_NUMBER

SIZEOF_DATE
SIZEOF_ANSI_Time
SIZEOF_ANSI_Time_WZone
SIZEOF_TimeStamp
SIZEOF_TimeStamp_WZone

SIZEOF_INTERVAL_YEAR
SIZEOF_IntrvlYtoM
SIZEOF_INTERVAL_MONTH
SIZEOF_INTERVAL_DAY
SIZEOF_IntrvlDtoH
SIZEOF_IntrvlDtoM
SIZEOF_IntrvlDtoS
SIZEOF_HOUR
SIZEOF_IntrvlHtoM
SIZEOF_IntrvlHtoS
SIZEOF_MINUTE
SIZEOF_IntrvlMtoS
SIZEOF_IntrvlSec

SIZEOF_UDT_HANDLE