Yes, yes!!
thank you, now I understand!!
Superb!
Thanks Michael!
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Black, Michael (IS)
Sent: Monday, June 25, 2012 11:03 AM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] C++ programming - Extracting data
You were doing two sqlite3_step()'s instead of one. So you skipped the one
record you had inserted.
You can run this multiple times and you;; see error messages about the
create table on 2nd and subsequent runs.
Still adds the same record though so you'll see +1 records get printed out
for every time you run it.
Here's a complete working example:
#include <iostream>
#include "sqlite3.h"
using namespace std;
// TEST BENCH
// 1. Create/Open a database 'db'
// 2. Add a table in the database 'friend'
// 3. add data to table friend
// 4. Extract the data from table friend and display it
sqlite3 *db;
void OpenDB() {
int rc;
string dbName = "arbol.db";
rc = sqlite3_open_v2(dbName.c_str(),
&db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
NULL);
if(rc != SQLITE_OK) { /* display error msg */
cerr << "Error???" << endl;
}
}
void CreateTable() {
string create_table = "CREATE TABLE friend (name TEXT, address TEXT, age
INT)";
sqlite3_stmt *stmt;
int rc = sqlite3_prepare_v2( db, create_table.c_str(), -1, &stmt, NULL );
if(rc != SQLITE_OK) {
cerr << "Error1: " << sqlite3_errmsg(db) << endl;
}
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) {
cerr << "Error2: " << sqlite3_errmsg(db) << endl;
}
sqlite3_finalize(stmt);
}
void Setter() {
string Name;
sqlite3_stmt *stmt;
string dbdata = "INSERT INTO friend (name, address, age) VALUES
('Caramba', '490 New Bridge', '49')";
int rc = sqlite3_prepare_v2(db,
dbdata.c_str(),dbdata.length(),&stmt,NULL);
if(rc != SQLITE_OK) {
cerr << "Error: " << sqlite3_errmsg(db) << endl;
}
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) {
cerr << "Error: " << sqlite3_errmsg(db) << endl;
}
sqlite3_finalize(stmt);
}
void getter() {
string sName;
string dbdata = "SELECT * FROM friend";
sqlite3_stmt *stmt;
int rc = sqlite3_prepare_v2(db, dbdata.c_str(), -1, &stmt, NULL );
if(rc != SQLITE_OK) {
cerr << "Error: " << sqlite3_errmsg(db) << endl;
}
while (sqlite3_step(stmt) == SQLITE_ROW) {
sName = (char*)sqlite3_column_text(stmt, 0);
//obj.Display(sName); //<== this is not display
cout << "sName=" << sName << endl;
}
sqlite3_finalize(stmt);
}
void theDestructor() {
int rc=sqlite3_close(db);
if (rc != SQLITE_OK) {
cerr << "Error: " << sqlite3_errmsg(db) << endl;
}
}
int main() {
OpenDB();
CreateTable();
Setter();
getter();
theDestructor();
return 0;
}
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: Monday, June 25, 2012 9:30 AM
To: 'General Discussion of SQLite Database'
Subject: EXT :Re: [sqlite] C++ programming - Extracting data
I did what you suggested, you were right, now the exception is gone, but the
program now does not display anything, it just goes to the end of the
method.
Here is a more complete snip of the test bench program. I really hope that
someone here can help resolve this issue.
// TEST BENCH
// 1. Create/Open a database 'db'
// 2. Add a table in the database 'friend'
// 3. add data to table friend
// 4. Extract the data from table friend and display it
OpenDB() {
rc = sqlite3_open_v2(dbName.c_str(),
&db, SQLITE_OPEN_READWRITE | SQLITE_OPEN_CREATE,
NULL);
if(rc != SQLITE_OK) { /* display error msg */ }
....
}
CreateTable() {
create_table = "CREATE TABLE friend (name TEXT, address TEXT, age INT)";
rc = sqlite3_prepare_v2( db, create_table.c_str(), -1, &stmt, NULL );
if(rc != SQLITE_OK) { /* display error msg */ }
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) { /* display error msg */ }
sqlite3_finalize(stmt);
}
Setter() {
string Name;
string dbdata = "INSERT INTO friend (name, address, age) VALUES
('Caramba', '490 New Bridge', '49')";
rc = sqlite3_prepare_v2(db, bdata.c_str(),dbdata.length(),&stmt,NULL);
if(rc != SQLITE_OK) { /* display error msg */ }
.....
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) { /* display error msg */}
sqlite3_finalize(stmt);
}
getter() {
string sName;
string dbdata = "SELECT * FROM friend";
rc = sqlite3_prepare_v2(db, dbdata.c_str(), -1, &stmt, NULL );
if(rc != SQLITE_OK) { /* display error msg */ }
....
rc = sqlite3_step(stmt);
if(rc != (SQLITE_DONE) && rc != (SQLITE_ROW)){ ... }
while (sqlite3_step(stmt) == SQLITE_ROW) {
sName = (char*)sqlite3_column_text(stmt, 0);
obj.Display(sName); //<== this is not display
...
}
sqlite3_finalize(stmt);
}
theDestructor() {
sqlite3_close(db);
}
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Black, Michael (IS)
Sent: Monday, June 25, 2012 9:39 AM
To: General Discussion of SQLite Database
Subject: Re: [sqlite] C++ programming - Extracting data
You're not doing the right sequencing...so your cout is only executing when
there is NOT a row.
Change
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) { ... }
while ( sqlite3_step(stmt) != SQLITE_ROW) {
sName = (char*)sqlite3_column_text(stmt, 0); //<== Seg fault
std::cout << sName << std::endl;
...
}
To
while ( sqlite3_step(stmt) == SQLITE_ROW) {
sName = (char*)sqlite3_column_text(stmt, 0); //<== Seg fault
std::cout << sName << std::endl;
...
}
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: Monday, June 25, 2012 8:27 AM
To: 'General Discussion of SQLite Database'
Subject: EXT :Re: [sqlite] C++ programming - Extracting data
Sorry, I forgot to give you a snip of the test-bench code
getter() {
string sName;
string sAddress;
int age = 0;
string dbdata = "SELECT * FROM friend";
rc = sqlite3_prepare_v2(db, dbdata.c_str(), -1, &stmt, NULL );
....
rc = sqlite3_step(stmt);
if(rc != SQLITE_DONE) { ... }
while ( sqlite3_step(stmt) != SQLITE_ROW) {
sName = (char*)sqlite3_column_text(stmt, 0); //<== Seg fault
std::cout << sName << std::endl;
...
}
sqlite3_finalize(stmt);
}
-----Original Message-----
From: [email protected]
[mailto:[email protected]] On Behalf Of Igor Tandetnik
Sent: Monday, June 25, 2012 9:07 AM
To: [email protected]
Subject: Re: [sqlite] C++ programming - creating a table
Arbol One <[email protected]> wrote:
> Q: What are you trying to achieve here? What's the supposed purpose of
> sqlite3_column_type call?
>
> A: What I am trying to do is to display the data in a data table
You run a SELECT statement for that. In any case, what data do you expect
there to be right after CREATE TABLE?
--
Igor Tandetnik
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http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
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