Working with SQL-Statements

With the classes ObjectLoader and the HSRecordSet SQL commands can be executed.

A HSRecordSet object is used to read data from a database. The HSRecordSet object has several getObject() methods, which return a specified object. Use one the methods.

Example:

try
{
    // Getting the connection
    ConnectionDescriptor des = ObjectLoader.getConnectionDescriptor(
                               "tables/example.connection");
    String sql = "SELECT lastname FROM KUNDEN";
    // Send the SQL statement
    HSRecordSet hsRecordSet = new HSRecordSet(sql, des);
    // The results number of rows
    int rowCount = hsRecordSet.getRowCount();
    // Outputting the result
    for (int i = 0; i < rowCount; i++) {
        hsRecordSet.absolute(i + 1);
        String name = (String) hsRecordSet.getObject(
            "lastname");
        System.out.println(i + ":" + name);
    }
} catch (Exception e) {
    e.printStackTrace();
}

Executing any SQL-Statement

Objects of the class QueryDescriptor used to execute sql statements in a database. The method getQueryDescriptor(String sqlStatement, boolean update) returns a QueryDescriptor. The attibute "sqlStatement" is the statement to execute. The attribute "update" must be true. After this call the method executeUpdate(queryDescriptor) of the class DBUtils.

Beispiel:

try
{
    QueryDescriptor queryDescriptor = DBUtils.
        getQueryDescriptor("DELETE FROM Kunden Where ID = 234", true);
    DBUtils.executeUpdate(queryDescriptor);
} catch (Exception e) {
    e.printStackTrace();
}

Examples for database commands