package de.sql.tests;
+import java.sql.CallableStatement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
+import java.sql.Types;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
private static final String DB_URL =
"jdbc:mysql://127.0.0.1:3306/n2a?autoReconnect=true&useUnicode=true&characterEncoding=UTF-8";
- public static void main(final String[] args) {
- Connection connection = null;
- Statement statement = null;
- ResultSet answer = null;
- PreparedStatement preparedStatement = null;
- try {
- // 1. Register JDBC driver
- //
- // Register JDBC driver (by itself) with the DriverManager!!!
- // (see static initializers in com.mysql.jdbc.Driver)
- //
- // otherwise, you could do it like this:
- // DriverManager.registerDriver(new Driver()); (it should be the same)
- //
- Class.forName("com.mysql.jdbc.Driver");
-
- // 2. Open a connection
- logger.info("Connecting to database");
- connection = DriverManager.getConnection(RawJDBCExample.DB_URL, "root", "");
+ public static void main(final String[] args) throws ClassNotFoundException, SQLException {
+
+ // 1. Register JDBC driver
+ //
+ // Register JDBC driver (by itself) with the DriverManager!!!
+ // (see static initializers in com.mysql.jdbc.Driver)
+ //
+ // otherwise, you could do it like this:
+ // DriverManager.registerDriver(new Driver()); (it should be the same)
+ //
+ Class.forName("com.mysql.jdbc.Driver");
+
+ // 2. Open a connection
+ logger.info("Connecting to database");
+ final Connection connection = DriverManager.getConnection(RawJDBCExample.DB_URL, "root", "");
+ try {
+
// 3. Execute some query: statement
logger.info("Execute statement");
- statement = connection.createStatement();
- answer = statement.executeQuery("SELECT * FROM AD");
- // Loop through ResultSet a row at a time
- while (answer.next()) {
- final int adID = answer.getInt("AD_ID");
- final int adCode = answer.getInt("AD_CODE");
- final String description = answer.getString("DESCRIPTION");
- logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
- }
+ executeStatement(connection);
logger.info("Statement executed successfully");
+
// 4. Execute some query: prepared statement
logger.info("Execute prepared statement");
- preparedStatement = connection.prepareStatement("SELECT * FROM AD");
- preparedStatement.executeQuery();
- // Loop through ResultSet a row at a time
- while (answer.next()) {
- final int adID = answer.getInt("AD_ID");
- final int adCode = answer.getInt("AD_CODE");
- final String description = answer.getString("DESCRIPTION");
- logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
- }
+ preparedStatement(connection);
logger.info("Prepared statement executed successfully");
- } catch (final ClassNotFoundException | SQLException e) {
- logger.error("Program error: ", e);
+
+
+ // 5. Execute some query: callable statement
+ // JDBC also supports the execution of stored
+ // procedures and stored functions through a third type of statement object,
+ // the CallableStatement object created by the prepareCall() method.
+ logger.info("Execute callable statement");
+ callableStatement(connection);
+ logger.info("Callable statement executed successfully");
+
} finally {
- if (answer != null) {
+ connection.close();
+ }
+ }
+
+ private static void executeStatement(final Connection connection) throws SQLException {
+ /**
+ * I MAY USE THE SAME Statement MORE THAN ONCE!!! :)
+ */
+
+ Statement statement = null;
+ ResultSet answer = null;
+ try {
+ statement = connection.createStatement();
+ answer = statement.executeQuery("SELECT * FROM AD");
+ // Loop through ResultSet a row at a time
+ while (answer.next()) {
+ final int adID = answer.getInt("AD_ID");
+ final int adCode = answer.getInt("AD_CODE");
+ final String description = answer.getString("DESCRIPTION");
+ logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
+ }
+ } finally {
+ if (answer != null) {
+ // Explicitly close the cursor and connection. NOTE: IT IS NOT THE SAME AS "DECLARE CURSOR" OF SQL
+ // This is a cursor in program memory not in DBMS!!!
+ try {
+ answer.close(); // Cursor
+ } catch (final SQLException e) {
+ logger.error("Error while closing cursor: ", e);
+ }
+ }
+ }
+
+
+ try {
+ answer = statement.executeQuery("SELECT * FROM AD");
+ // Loop through ResultSet a row at a time
+ while (answer.next()) {
+ final int adID = answer.getInt("AD_ID");
+ final int adCode = answer.getInt("AD_CODE");
+ final String description = answer.getString("DESCRIPTION");
+ logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
+ }
+ } finally {
+ if (answer != null) {
// Explicitly close the cursor and connection. NOTE: IT IS NOT THE SAME AS "DECLARE CURSOR" OF SQL
// This is a cursor in program memory not in DBMS!!!
try {
}
}
if (statement != null) {
- // I think closing ResultSet should be enough...
try {
statement.close();
} catch (final SQLException e) {
logger.error("Error while closing statement: ", e);
}
}
- if (preparedStatement != null) {
- // I think closing ResultSet should be enough...
+ }
+ }
+
+ private static void preparedStatement(final Connection connection) throws SQLException {
+ /**
+ * I MAY USE THE SAME PreparedStatement MORE THAN ONCE!!! :)
+ */
+
+ PreparedStatement preparedStatement = null;
+ ResultSet answer = null;
+ try {
+ preparedStatement = connection.prepareStatement("SELECT * FROM AD");
+ answer = preparedStatement.executeQuery();
+ // Loop through ResultSet a row at a time
+ while (answer.next()) {
+ final int adID = answer.getInt("AD_ID");
+ final int adCode = answer.getInt("AD_CODE");
+ final String description = answer.getString("DESCRIPTION");
+ logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
+ }
+ } finally {
+ if (answer != null) {
+ // Explicitly close the cursor and connection. NOTE: IT IS NOT THE SAME AS "DECLARE CURSOR" OF SQL
+ // This is a cursor in program memory not in DBMS!!!
try {
- preparedStatement.close();
+ answer.close(); // Cursor
} catch (final SQLException e) {
- logger.error("Error while closing prepared statement: ", e);
+ logger.error("Error while closing cursor: ", e);
}
}
- if (connection != null) {
+ }
+
+
+ try {
+ answer = preparedStatement.executeQuery();
+ // Loop through ResultSet a row at a time
+ while (answer.next()) {
+ final int adID = answer.getInt("AD_ID");
+ final int adCode = answer.getInt("AD_CODE");
+ final String description = answer.getString("DESCRIPTION");
+ logger.info("AD_ID: " + adID + " AD_CODE: " + adCode + " DESCRIPTION: " + description);
+ }
+ } finally {
+ if (answer != null) {
+ // Explicitly close the cursor and connection. NOTE: IT IS NOT THE SAME AS "DECLARE CURSOR" OF SQL
+ // This is a cursor in program memory not in DBMS!!!
try {
- connection.close();
+ answer.close(); // Cursor
} catch (final SQLException e) {
- logger.error("Error while closing connection: ", e);
+ logger.error("Error while closing cursor: ", e);
}
}
- }
+ if (preparedStatement != null) {
+ try {
+ preparedStatement.close();
+ } catch (final SQLException e) {
+ logger.error("Error while closing statement: ", e);
+ }
+ }
+ }
+ }
+
+ private static void callableStatement(final Connection connection) throws SQLException {
+ /**
+ * CREATE PROCEDURE CHANGE_REGION
+ * (IN OFFICE INTEGER,
+ * OUT OLD_REG VARCHAR(10),
+ * IN NEW_REG VARCHAR(10))
+ *
+ * CREATE FUNCTION GET_REGION
+ * (IN OFFICE INTEGER)
+ * RETURNS VARCHAR(10)
+ */
+
+ CallableStatement cstmt1 = null;
+ CallableStatement cstmt2 = null;
+ try {
+ // Stored procedure:
+ final String str1 = "{CALL CHANGE_REGION(?, ?, ?)}";
+ // Stored function:
+ final String str2 = "{? = CALL GET_REGION(?)}";
+
+ // Prepare the two statements
+ cstmt1 = connection.prepareCall(str1);
+ cstmt2 = connection.prepareCall(str2);
+
+ // Go ahead and execute the call to the stored procedure
+ cstmt1.executeUpdate();
+ final String adCode = cstmt1.getString("AD_CODE");
+
+ cstmt2.setInt("AD_ID", 666);
+ cstmt2.setString("AD_DESCRIPTION", "My ad");
+ // returns a varchar parameter
+ cstmt2.registerOutParameter("AD_DESCRIPTION", Types.VARCHAR);
+ // Go ahead and execute the call to the stored function
+ cstmt2.executeUpdate();
+ } finally {
+ try {
+ cstmt1.close();
+ } catch (final SQLException e) {
+ logger.error("Error while closing statement: ", e);
+ }
+ try {
+ cstmt2.close();
+ } catch (final SQLException e) {
+ logger.error("Error while closing statement: ", e);
+ }
+ }
}
}
projects / JavaForFun / commitdiff