Re: [sqlite] C++ programming - Extracting data

[Arbol One]

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: sqlite-users-boun...@sqlite.org
[mailto:sqlite-users-boun...@sqlite.org] 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: sqlite-users-boun...@sqlite.org [sqlite-users-boun...@sqlite.org] on
behalf of Arbol One [arbol...@gmail.com]
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: sqlite-users-boun...@sqlite.org
[mailto:sqlite-users-boun...@sqlite.org] On Behalf Of Igor Tandetnik
Sent: Monday, June 25, 2012 9:07 AM
To: sqlite-users@sqlite.org
Subject: Re: [sqlite] C++ programming - creating a table

Arbol One <arbol...@gmail.com> 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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