const Status QU_Select(const string & result,
const int projCnt,
const attrInfo projNames[],
const attrInfo *attr,
const Operator op,
const char *attrValue)
{
// Qu_Select sets up things and then calls ScanSelect to do the actual work
cout << "Doing QU_Select " << endl;
Status s;
AttrDesc attrDesc;
AttrDesc* projAttrInfo = new AttrDesc[projCnt];
int length = 0;
for(int i = 0; i < projCnt; i++){
s = attrCat->getInfo(projNames[i].relName, projNames[i].attrName, projAttrInfo[i]);
if(s != OK) return s;
length += projAttrInfo[i].attrLen;
}
if(attr == NULL)
{
s = ScanSelect(result, projCnt, projAttrInfo,NULL, op, NULL, length);
if(s != OK) return s;
}
else
{
s=attrCat->getInfo(attr->relName, attr->attrName, attrDesc);
if(s != OK) return s;
int i;
float f;
switch(attrDesc.attrType)
{
case INTEGER:
{
i = atoi(attrValue);
attrValue = (char *)&i;
break;
}
case FLOAT:
{
f = atof(attrValue);
attrValue = (char *)&f;
break;
}
case STRING:
{
//do nothing
break;
}
}
s = ScanSelect(result, projCnt, projAttrInfo, &attrDesc, op, attrValue, length);
if(s != OK) return s;
}
delete projAttrInfo;
return s;
}
const Status QU_Select(const string & result,
const int projCnt,
const attrInfo projNames[],
const attrInfo *attr,
const Operator op,
const char *attrValue)
{
// Qu_Select sets up things and then calls ScanSelect to do the actual work
cout << "Doing QU_Select " << endl;
Status status;
// go through the projection list and look up each in the
// attr cat to get an AttrDesc structure (for offset, length, etc)
AttrDesc attrDescArray[projCnt];
for (int i = 0; i < projCnt; i++)
{
Status status = attrCat->getInfo(projNames[i].relName,
projNames[i].attrName,
attrDescArray[i]);
if (status != OK)
{
return status;
}
}
// get output record length from attrdesc structures
int reclen = 0;
for (int i = 0; i < projCnt; i++)
{
reclen += attrDescArray[i].attrLen;
}
if (attr){
// get AttrDesc structure for the select attribute
AttrDesc attrDesc1;
status = attrCat->getInfo(attr->relName,
attr->attrName,
attrDesc1);
if (status != OK)
{
return status;
}
return ScanSelect(result, projCnt, attrDescArray, &attrDesc1, op, attrValue, reclen);
} else {
return ScanSelect(result, projCnt, attrDescArray, NULL, op, attrValue, reclen);
}
}
const Status QU_Select(const string & result,
const int projCnt,
const attrInfo projNames[],
const attrInfo *attr, //If null, unconditional scan
const Operator op,
const char *attrValue)
{
// Qu_Select sets up things and then calls ScanSelect to do the actual work
cout << "Doing QU_Select " << endl;
Status status;
AttrDesc projNames_Descs[projCnt];
for (int i = 0; i < projCnt; i++)
{
status = attrCat->getInfo(projNames[i].relName, projNames[i].attrName, projNames_Descs[i]);
if (status != OK)
return status;
}
AttrDesc *attrDescWhere = NULL;
int attrValueLen = 0;
if(attr != NULL)
{
attrDescWhere = new AttrDesc;
status = attrCat->getInfo(attr->relName, attr->attrName, *attrDescWhere);
attrValueLen = attrDescWhere->attrLen;
if (status != OK)
return status;
}
return ScanSelect( result,
projCnt,
projNames_Descs,
attrDescWhere,
op,
attrValue,
attrValueLen);
}
const Status QU_Select(const string & result,
const int projCnt,
const attrInfo projNames[],
const attrInfo *attr,
const Operator op,
const char *attrValue)
{
// Qu_Select sets up things and then calls ScanSelect to do the actual work
cout << "Doing QU_Select " << endl;
Status status;
AttrDesc attrDesc;
int intval;
float floatval;
const char *filter;
AttrDesc* projDescs = new AttrDesc[projCnt];
for(int i = 0; i < projCnt; i++){
if((status = attrCat->getInfo(projNames[i].relName, projNames[i].attrName, projDescs[i])) != OK){
return status;
}
}
if(attr == NULL){//unconditonal selection
}else if((status =attrCat-> getInfo(attr->relName, attr->attrName, attrDesc)) != OK){
return status;
}
//get output record length from attrdesc strucres
int reclen = 0;
for (int i = 0; i < projCnt; i++){
reclen += projDescs[i].attrLen;
}
if(attr == NULL){
if ((status = ScanSelect(result, projCnt, projDescs,NULL, op, NULL, reclen)) != OK){
return status;
}
}else{
switch(attrDesc.attrType){
case INTEGER:
intval = atoi(attrValue);
filter = (char *)&intval;
break;
case FLOAT:
floatval = atof(attrValue);
filter = (char *)&floatval;
break;
default:
filter = attrValue;
break;
}
if((status = ScanSelect(result, projCnt, projDescs, &attrDesc, op, filter, reclen)) != OK){
return status;
}
}
delete [] projDescs;
return OK;
}
/*
* Selects records from the specified relation using a
* HeapFileScan. The project list is defined by
* the parameters projCnt and projNames and is done on-the-fly.
* <i>The search value is always supplied as the character string attrValue.
* If attr is NULL, an unconditional scan of the input table should be performed.</i>
*
* @param result
* @param projCnt
* @param projNames[]
* @param attr
* @param op
* @param attrValue
* @return: OK on success
* an error code otherwise
*/
const Status QU_Select(const string & result,
const int projCnt,
const attrInfo projNames[],
const attrInfo *attr,
const Operator op,
const char *attrValue)
{
Status status;
AttrDesc attrDesc;
AttrDesc* projNamesDesc;
int reclen;
Operator myOp;
const char* filter;
reclen = 0;
//an array of attrDesc to hold all the descriptions for the projection
projNamesDesc = new AttrDesc[projCnt];
//tabulate the total length of the projection record
for (int i = 0; i < projCnt; i++) {
Status status = attrCat->getInfo(projNames[i].relName, projNames[i].attrName, projNamesDesc[i]);
reclen += projNamesDesc[i].attrLen;
if (status != OK) { return status; }
}
//implementation of select operation
if (attr != NULL) { //SELECT ALL
//get info for attr
//e.g. attr op attrvalue
status = attrCat->getInfo(string(attr->relName), string(attr->attrName), attrDesc);
int tmpInt;
float tmpFloat;
//convert to proper data type
switch (attr->attrType) {
case INTEGER:
tmpInt = atoi(attrValue);
filter = (char*)&tmpInt;
break;
case FLOAT:
tmpFloat = atof(attrValue);
filter = (char*)&tmpFloat;
break;
case STRING:
filter = attrValue;
break;
}
myOp = op;
//if null than there is no where clause
//select all tuple for projection attributes
} else {
//default attrDesc for an unconditional scan
strcpy(attrDesc.relName, projNames[0].relName);
strcpy(attrDesc.attrName, projNames[0].attrName);
attrDesc.attrOffset = 0;
attrDesc.attrLen = 0;
attrDesc.attrType = STRING;
filter = NULL;
myOp = EQ;
}
//now that the book keeping is done call ScanSelect to actually build the result table
status = ScanSelect(result, projCnt, projNamesDesc, &attrDesc, myOp, filter, reclen);
if (status != OK) { return status; }
return OK;
}
