SQL/MX 3.2.1 Programming Manual for C and COBOL (H06.26+, J06.15+)

Static Rowsets
HP NonStop SQL/MX Release 3.2.1 Programming Manual for C and COBOL—663854-005
7-4
Rowset Host Variable Pointers
Rowset Host Variable Pointers
A rowset host variable cannot be declared as a pointer. If you need to access a rowset
host variable through a pointer, you must make the rowset host variable a structure
field.
Example
The following example shows an improper usage of rowset host variable where the
rowset host variable is declared as a pointer type:
EXEC SQL BEGIN DECLARE SECTION;
/* cannot declare a rowset pointer as host variable */
ROWSET [100] int * rowsetPtr;
...
The following example shows the correct use of rowsets in a structure:
EXEC SQL BEGIN DECLARE SECTION;
struct ptrType
{
/* rowsets are allowed as structure fields */
ROWSET [100] int rowsetField;
...
};
struct ptrType * structPtr;
...
Considerations for Rowset Size

The total rowset size (that is, the size of the row times the number of rows) should
not produce fragmentation in the network or process communication.

The total rowset size should not exceed the physical memory of the client
computer to avoid fragmentation while accessing a rowset array.

The rowset size should not be less than the number of rows that need to be
accessed simultaneously. For example, a screen-based application should use a
rowset size that is a multiple of the number of rows displayed on the screen.
Specifying Rowset Arrays
After you declare a host variable array that is a part of a rowset, use this syntax to
specify it within an embedded SQL statement.
array-name
is the host variable array name. It can be any valid host language identifier with a
data type that corresponds to an SQL data type. You must precede array-name
with a colon (:) within an SQL statement.
:array-name [[INDICATOR] :indicator-array-name]