C/C++ DBMS API

Today, I gave a fast look to some popular SQL database API. If you want to dig them, I suggest you to have a look to the Qt library - the database driver part.

PostgreSQL pgsql API

Free. Actually, the main problem is more PostgreSQL than the API. PostgreSQL is supposedly better than MySQL, but setting up the database server is somewhat complex (on a unix system; it seems to be easier on a Windows system) and it seems that MySQL is faster. It supports atomic transactions.

The API is C oriented, and is farily simple. The function used to send a SQL query is:

PGresult *PQexec(PGconn *conn, const char *command);

To retrieve the results, I have to use

// to test the PGresult status:ExecStatusType PQresultStatus(const PGresult *res);// to count the number of tuplesint PQntuples(const PGresult *res);// to get the number of column in each tupleint PQnfields(const PGresult *res);// to get the type of a columnOid PQftype(const PGresult *res, int column_number);// to get the valuechar *PQgetvalue(const PGresult *res, int row_number, int column_number);

SQLite API

Free too. No dependencies (SQLite doesn't connect to a database, it stores your datas in plain files) but is limited to a subset of SQL.

The API is very simple too: it is described here.

int sqlite3_exec(sqlite3*, const char *sql, sqlite_callback, void*, char**);

Is used to send a SQL query to the engine. Newt, we use

int sqlite3_column_count(sqlite3_stmt *pStmt);int sqlite3_column_type(sqlite3_stmt*, int iCol);

sqlite3_column_XXX() functions are used to read the data.

There is an atomic transaction management.

MySQL API

Free for open-source use (which is not my plan at all); otherwise it is not very expensive - well... It can be...

The InnoDB table engine provide the needed atomic transactions.

The API is very simple too: there is a bunch of mysql_* C function that are rather easy to use. There is also a C++ API (which can be found here) - and that's a very good point (because, take it or not, I program in C++).

Here is a simple example of the MySQL++ API.

Of course, if you know some other SQL API (either C or C++), I encourage you to post a comment here ;)