Question

How can I create a local database inside a Microsoft Visual C++ 2010 Express project?

I can’t find this simple answer in the web. The only answer I’ve found is for Visual Studio: using project > add new item > local database. But this option isn’t available in Visual c++ 2010 Express edition.

I tried installing "Microsoft SQL Server Compact 4" and "Microsoft SQL Server Denali", and updating "Microsoft Visual C++ 2010 Express" from "Windows Update".

Answer 1

Ok, I got a solution at last. Regrettably I must answer my own question…

I used SQLite library (http://www.sqlite.org/). It was a little complicated because the sqlite documentation is a bit vague, but I did as follows:

• Download sqlitedll*.zip – extract .def and .dll files somewhere.
• Generate the lib file with a command like “c:\program
  files\micros~1\vc98\bin\lib” /def:sqlite3.def”. Do that from a command
  prompt, in the directory with the .def file in, with the appropriate
  path to your lib.exe. You may need to run vcvars32.bat first, which is
  also in the bin directory. Copy the resulting .lib to an appropriate
  place, and set that as a library directory in VC++. (Or do it on a
  per-project basis.)
• Download the sqlite-source*.zip file, and extract the sqlite3.h file
  from within to a suitable directory. Set that as an include directory
  in VC++. (Again, you could do it on a per-project basis.)
• In your project, #include as required, add sqlite3.lib
  to your project, copy the sqlite3.dll to your executable’s directory
  or working directory, and you should be ready to go.

Then, is easy to use no-out queries, but if you want to use a SQL “SELECT” for example, you could use this code:

std::string queries;
// A prepered statement for fetching tables
sqlite3_stmt *stmt;
// Create a handle for database connection, create a pointer to sqlite3
sqlite3 *handle;
// try to create the database. If it doesnt exist, it would be created
// pass a pointer to the pointer to sqlite3, in short sqlite3**
int retval = sqlite3_open("local.db",&handle);
// If connection failed, handle returns NULL
if(retval){
    System::Windows::Forms::MessageBox::Show("Database connection failed");
    return;
}       
// Create the SQL query for creating a table
char create_table[100] = "CREATE TABLE IF NOT EXISTS users (uname TEXT PRIMARY KEY,pass TEXT NOT NULL,activated INTEGER)";
// Execute the query for creating the table
retval = sqlite3_exec(handle,create_table,0,0,0);
// Insert first row and second row
queries = "INSERT INTO users VALUES('manish','manish',1)";
retval = sqlite3_exec(handle,queries.c_str(),0,0,0);
queries = "INSERT INTO users VALUES('mehul','pulsar',0)";
retval = sqlite3_exec(handle,queries.c_str(),0,0,0);
// select those rows from the table
queries = "SELECT * from users";
retval = sqlite3_prepare_v2(handle,queries.c_str(),-1,&stmt,0);
if(retval){
    System::Windows::Forms::MessageBox::Show("Selecting data from DB Failed");
    return ;
}
// Read the number of rows fetched
int cols = sqlite3_column_count(stmt);
while(1){
    // fetch a row’s status
    retval = sqlite3_step(stmt);
    if(retval == SQLITE_ROW){
    // SQLITE_ROW means fetched a row
    // sqlite3_column_text returns a const void* , typecast it to const char*
        for(int col=0 ; col<cols;col++){
            const char *val = (const char*)sqlite3_column_text(stmt,col);
            System::Windows::Forms::MessageBox::Show(stdstr2systemstr(sqlite3_column_name(stmt,col))+" = "+stdstr2systemstr(val));
        }
    }
    else
    if(retval == SQLITE_DONE){
            // All rows finished
            System::Windows::Forms::MessageBox::Show("All rows fetched");
            break;
        }
        else{
            // Some error encountered
            System::Windows::Forms::MessageBox::Show("Some error encountered");
            return ;
        }
    }
    // Close the handle to free memory
    sqlite3_close(handle);

I expect this info be useful!

Sources:

• http://www.gamedev.net/topic/332251-sqlite3-and-visual-c/page_p_3157685#entry3157685
• http://milky.manishsinha.net/2009/03/30/sqlite-with-c/