[HACKERS] Decimal values in
Dear Dev-List,
inside execProcnode.c's ExecProcNode method we want to extract the value of
a tuple for a specific attribute. This works great for integers and
strings, but we are not able to figure out how to do this for floating
point numbers. Below is some example code snippet to show our problem:
TupleTableSlot *
ExecProcNode(PlanState *node) {
TupleTableSlot *result;
...
bool isNull;
Datum datum = slot_getattr(result,0, isNull);
Form_pg_attribute *attrList = result-tts_tupleDescriptor-attrs;
if(attrList[0]-atttypid==INT4OID){
int value = (int) (datum);
...
} else if(attrList[0]-atttypid==VARCHAROID){
char* value = TextDatumGetCString(datum);
...
//this does not work :(
} else if(attrList[0]-atttypid==DECIMAL_OID /*what is the right
OID*/){
//the value does not seem to be stored in the datum
float value = (float) (datum);
...
}
...
}
How can we get those values?
Yours sincerely, Fabian Tschirschnitz.
Re: [HACKERS] Decimal values in
Masterprojekt Naumann1 escribió: Dear Dev-List, inside execProcnode.c's ExecProcNode method we want to extract the value of a tuple for a specific attribute. This works great for integers and strings, but we are not able to figure out how to do this for floating point numbers. Below is some example code snippet to show our problem: DECIMAL_OID (you probably mean NUMERICOID) points to datatype numeric, which is not floating point but a variable length datatype with its own special encoding for storage. If you want floating point you need FLOAT4OID and FLOAT8OID, and columns created with types float and double precision, respectively. -- Álvaro Herrerahttp://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
Re: [HACKERS] Decimal values in
Alvaro Herrera alvhe...@2ndquadrant.com writes: Masterprojekt Naumann1 escribió: inside execProcnode.c's ExecProcNode method we want to extract the value of a tuple for a specific attribute. This works great for integers and strings, but we are not able to figure out how to do this for floating point numbers. Below is some example code snippet to show our problem: DECIMAL_OID (you probably mean NUMERICOID) points to datatype numeric, which is not floating point but a variable length datatype with its own special encoding for storage. If you want floating point you need FLOAT4OID and FLOAT8OID, and columns created with types float and double precision, respectively. Also, you should not be using casts, but the appropriate DatumGetXXX macro. In some cases those reduce to a cast, but your code ought not assume that. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
