yes, it worked, thanks Michael.
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Black, Michael (IS)
Sent: Wednesday, September 12, 2012 8:13 AM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] C++ - HOW MANY rows?
Try using this method...you just need to ensure mystmt is set to NULL to
start with and reset to NULL in finalize().
const int mySQLite3::read_int(int pos)
throw(somexception) {
if (mystmt == NULL) { // Ensure mystmt is set to NULL in constructor
rc = sqlite3_prepare_v2(db, SQLStatement.c_str(), -1, &mystmt, NULL);
if(rc != SQLITE_OK) {
try {
this->display(rc, FILE, METHOD, LINE);
} catch(somexception e) {
throw e;
}
}
}
rc = sqlite3_step(mystmt);
if(rc == SQLITE_ROW ) {
apint = sqlite3_column_int(mystmt,pos);
counter++;
return apint;
}
if (rc != SQLITE_DONE) {
this->display(rc,FILE,METHOD,LINE+":"+sqlite3_errmsg(db));
}
try {
this->finalize(); // ensure mystmt set to null in finalize
} catch(somexception& e) {
throw e;
}
return -1; // how do you know when you're done? Will -1 work?
}
Michael D. Black
Senior Scientist
Advanced Analytics Directorate
Advanced GEOINT Solutions Operating Unit Northrop Grumman Information
Systems
________________________________________
From: [email protected] [[email protected]] on
behalf of Arbol One [[email protected]]
Sent: Tuesday, September 11, 2012 9:44 PM
To: 'General Discussion of SQLite Database'
Subject: EXT :Re: [sqlite] C++ - HOW MANY rows?
Thanks Igor for your prompt response.
Since the call to the sqlite3_step function is inside the mySQLite3::read_*
class-function/method, I call the read_* method from Runner::read_tblName()
for each datum I need to retrieve. Now, in a while loop inside
Runner::read_tblName() I could call the mySQLite3::read_* for the data to be
retrieved, but instead of reading the next row of data, it keeps on reading
the same row again and again. Furthermore, I have no way to let
Runner::read_tblName 'know' that there is no more data, hence stopping the
while loop.
Obviously my problem is in design, but I don't have enough experience using
SQLite3 to come up with a better idea.
My question is, really, how do you, C++ programmers, have resolved this
issue? There must be a solution.
void Runner::read_tblName() {
.
sql_statement = "SELECT * FROM name"; //while(there is more data){ // I
have no-way to report to this method that there is no more data in the bank
// I could add a flag to the mySQLite3 class and have the while loop check
on its status, // or a signal that would be trigger by the ending of the
while loop.
db->setStmt(sql_statement);
int pos = 0;
data1 = db->read_int(pos);
db->setStmt(sql_statement);
pos = 1;
data2 = db->read_str(pos);
data3 = db->read_str(++pos);
data4 = db->read_str(++pos);
data5 = db->read_str(++pos);
Glib::ustring str;
str = apstr.format(data1);
str += " ";
str += data2;
str += ". ";
str += data3;
str += " ";
str += data4;
str += " ";
str += data5;
apex->setException(str, FILE, METHOD, LINE);
apex->Display();
// } <<<---
}
const int mySQLite3::read_int(int pos)
throw(somexception) {
rc = sqlite3_prepare_v2(db, SQLStatement.c_str(), -1, &mystmt, NULL);
if(rc != SQLITE_OK) {
try {
this->display(rc, FILE, METHOD, LINE);
} catch(somexception e) {
throw e;
}
} else {
counter++;
}
rc = sqlite3_step(mystmt);
if(rc == SQLITE_ROW ) {
apint = sqlite3_column_int(mystmt,pos);
}
try {
this->finalize();
} catch(somexception& e) {
throw e;
}
return apint;
}
const Glib::ustring& mySQLite3::read_str(const int pos)
throw(somexception) {
//if(pos == 0) {
rc = sqlite3_prepare_v2(db, this->SQLStatement.c_str(), -1, &mystmt,
NULL);
//}
if(rc != SQLITE_OK) {
try {
this->display(rc, FILE, METHOD, LINE);
} catch(somexception e) {
throw e;
}
} else {
counter++;
}
rc = sqlite3_step(mystmt);
if(rc == SQLITE_ROW ) {
apstr = (const char*)sqlite3_column_text(mystmt,pos);
}
try {
this->finalize();
} catch(somexception& e) {
throw e;
}
return apstr;
}
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