Application development with C/C++ - DB2 Express-C: The Developer for XML, PHP, C/C++, Java, and .NET - page 186

Example 4-33 Using SQLConnect() & SQLDisconnect()

SQLConnect(conn_handle, "sample", SQL_NTS, NULL, SQL_NTS, NULL,
SQL_NTS);
…
SQLDisconnect(conn_handle);

4.5.5 Processing SQL statements

After connecting to the database, we need to allocate a statement handle to
manage our SQL statement. Once this is done, we can execute an SQL
statement by either preparing the statement or executing the statement directly.
Figure 4-2 illustrates this process.

SQLPrepare()

SQLBindParameter()

SQLBindParameter()

SQLExecDirect()

SQLExecute()

Prepare and execute

Execute directly

Figure 4-2 Processing SQL statements

In either case, if parameter markers exist in the SQL statement,
SQLBindParameter() must be called to associate each parameter marker to an
application buffer or a LOB locator. If a SELECT statement is run and a result set
expected, a cursor is automatically opened. So, unlike embedded SQL, cursors
neither have to be declared nor opened. To fetch the results, SQLBindCol() is
first called to bind the columns of a result set to application variables, then
SQLFetch() is called to fetch the rows.