Java Coding Question And Answers

Connecting to a Database

This example uses the JDBC-ODBC bridge to connect to a database called ''mydatabase''.

try {
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
String url = "jdbc:odbc:mydatabase";
Connection con = DriverManager.getConnection(url, "login", "password");
} catch (ClassNotFoundException e) {
} catch (SQLException e) {
}

Creating a Table

This example creates a table called ''mytable'' with three columns: COL_A which holds strings, COL_B which holds integers, and COL_C which holds floating point numbers.

try {
Statement stmt = con.createStatement();
stmt.executeUpdate("CREATE TABLE mytable (COL_A VARCHAR(100), COL_B INTEGER, COL_C FLOAT)");
} catch (SQLException e) {
}

Entering a New Row into a Table

This example enters a row containing a string, an integer, and a floating point number into the table called ''mytable''.

try {

Statement stmt = connection.createStatement();
stmt.executeUpdate("INSERT INTO mytable VALUES ('Patrick Chan', 123, 1.23)");
connection.close();
} catch (SQLException e) {}

Getting All Rows from a Table

This example retrieves all the rows from a table called ''mytable''. A row in ''mytable'' consists of a string, integer, and floating point number.

try {
Statement stmt = connection.createStatement();
// Get data using column names.
ResultSet rs = stmt.executeQuery("SELECT * FROM mytable");

while (rs.next()) {
String s = rs.getString("COL_A");
int i = rs.getInt("COL_B");
float f = rs.getFloat("COL_C");
process(s, i, f);
}
// Get data using column numbers.
rs = stmt.executeQuery("SELECT * FROM mytable");

while (rs.next()) {
String s = rs.getString(1);
int i = rs.getInt(2);
float f = rs.getFloat(3);
process(s, i, f);
}
} catch (SQLException e) {}