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8.3. Issuing a Query and Processing the Result

Any time you want to issue SQL statements to the database, you require a Statement or PreparedStatement instance. Once you have a Statement or PreparedStatement, you can use issue a query. This will return a ResultSet instance, which contains the entire result. Example 8-1 illustrates this process.

Example 8-1. Processing a Simple Query in JDCB

This example will issue a simple query and print out the first column of each row using a Statement.

Statement st = db.createStatement();
ResultSet rs = st.executeQuery("SELECT * FROM mytable where columnfoo = 500");
while(rs.next()) {
    System.out.print("Column 1 returned ");
    System.out.println(rs.getString(1));
}
rs.close();
st.close();

This example will issue the same query as before using a PreparedStatement and a bind value in the query.

int foovalue = 500;
PreparedStatement st = db.prepareStatement("SELECT * FROM mytable where columnfoo = ?");
st.setInt(1, foovalue);
ResultSet rs = st.executeQuery();
while(rs.next()) {
    System.out.print("Column 1 returned ");
    System.out.println(rs.getString(1));
}
rs.close();
st.close();

8.3.1. Using the Statement or PreparedStatement Interface

The following must be considered when using the Statement or PreparedStatement interface:

8.3.2. Using the ResultSet Interface

The following must be considered when using the ResultSet interface: