Java by API/java.sql/Connection

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Connection: close()

   <source lang="java">

/* 

* */

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   if (conn != null) {
     System.out.println("Connection attempt was successful!");
     try {
       conn.close();
     } catch (SQLException ex) {
       ex.printStackTrace();
       System.out.println("Problem closing the connection");
     }
   }
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection: commit()

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   Connection conn = getConnection();
   conn.setAutoCommit(false);
   Statement st = conn.createStatement();
   st.executeUpdate("create table survey (id int,myURL CHAR);");
   String str = conn.nativeSQL("insert into survey(id) values(02)");
   System.out.println(str);
   
   conn.rumit();    
   st.close();
   conn.close();
 }
 private static Connection getConnection() throws Exception {
   Class.forName("org.hsqldb.jdbcDriver");
   String url = "jdbc:hsqldb:mem:data/tutorial";
   return DriverManager.getConnection(url, "sa", "");
 }

} 


 </source>



Connection: createStatement()

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   setup();
 }
 static Connection conn;
 static Statement st;
 public static void setup() {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection: createStatement(int resultSetType, int resultSetConcurrency)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class Main { 

 public static void main(String[] argv) throws Exception {
   String driverName = "com.jnetdirect.jsql.JSQLDriver";
   Class.forName(driverName);
   String serverName = "127.0.0.1";
   String portNumber = "1433";
   String mydatabase = serverName + ":" + portNumber;
   String url = "jdbc:JSQLConnect://" + mydatabase;
   String username = "username";
   String password = "password";
   Connection connection = DriverManager.getConnection(url, username, password);
   // Create a statement that will return updatable result sets
   Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
   // Primary key must be specified so that the result set is updatable
   ResultSet resultSet = stmt.executeQuery("SELECT col_string FROM my_table");
 }

} 


 </source>



Connection: getAutoCommit()

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Statement; public class Main { 

 public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   boolean executeResult;
   try {
     String driver = "oracle.jdbc.driver.OracleDriver";
     Class.forName(driver).newInstance();
     System.out.println("Connecting to database...");
     String jdbcUrl = "jdbc:oracle:thin:@localhost:1521:ORCL";
     conn = DriverManager.getConnection(jdbcUrl, "yourName", "mypwd");
     stmt = conn.createStatement();
     conn.setAutoCommit(false);
     if (!conn.getAutoCommit())
       System.out.println("Auto-commit is set to false");
     String sql = "INSERT INTO Location VALUES(715,"Houston")";
     stmt.executeUpdate(sql);
     sql = "INSERT INTO Employees VALUES" + "(8,"K","4351",{d "2000-02-00"},715)";
     stmt.executeUpdate(sql);
     conn.rumit();
   } catch (SQLException se) {
     String msg = se.getMessage();
     msg = "SQLException occured with message: " + msg;
     System.out.println(msg);
     System.out.println("Starting rollback operations...");
     try {
       conn.rollback();
     } catch (SQLException se2) {
       se2.printStackTrace();
     }
   } catch (Exception e) {
     e.printStackTrace();
   } 
 }

} 


 </source>



Connection: getMetaData()

   <source lang="java">

/* Driver Loaded. Got Connection. SYSTEM_ALIASES SYSTEM_ALLTYPEINFO SYSTEM_AUTHORIZATIONS SYSTEM_BESTROWIDENTIFIER SYSTEM_CACHEINFO SYSTEM_CATALOGS SYSTEM_CHECK_COLUMN_USAGE SYSTEM_CHECK_CONSTRAINTS SYSTEM_CHECK_ROUTINE_USAGE SYSTEM_CHECK_TABLE_USAGE SYSTEM_CLASSPRIVILEGES SYSTEM_COLLATIONS SYSTEM_COLUMNPRIVILEGES SYSTEM_COLUMNS SYSTEM_CROSSREFERENCE SYSTEM_INDEXINFO SYSTEM_PRIMARYKEYS SYSTEM_PROCEDURECOLUMNS SYSTEM_PROCEDURES SYSTEM_PROPERTIES SYSTEM_ROLE_AUTHORIZATION_DESCRIPTORS SYSTEM_SCHEMAS SYSTEM_SCHEMATA SYSTEM_SEQUENCES SYSTEM_SESSIONINFO SYSTEM_SESSIONS SYSTEM_SUPERTABLES SYSTEM_SUPERTYPES SYSTEM_TABLEPRIVILEGES SYSTEM_TABLES SYSTEM_TABLETYPES SYSTEM_TABLE_CONSTRAINTS SYSTEM_TEXTTABLES SYSTEM_TRIGGERCOLUMNS SYSTEM_TRIGGERS SYSTEM_TYPEINFO SYSTEM_UDTATTRIBUTES SYSTEM_UDTS SYSTEM_USAGE_PRIVILEGES SYSTEM_USERS SYSTEM_VERSIONCOLUMNS SYSTEM_VIEWS SYSTEM_VIEW_COLUMN_USAGE SYSTEM_VIEW_ROUTINE_USAGE SYSTEM_VIEW_TABLE_USAGE 

* */

import java.sql.Connection; import java.sql.DatabaseMetaData; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   DatabaseMetaData md = conn.getMetaData();
   ResultSet rs = md.getTables(null, null, "%", null);
   while (rs.next()) {
     System.out.println(rs.getString(3));
   }  }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection: getTransactionIsolation()

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection: getWarnings()

   <source lang="java">

import java.io.PrintWriter; import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.SQLWarning; public class Main { 

 public static void main(String[] args) throws Exception {
   String dbURL = "jdbc:odbc:Companies";
   try {
     // Load the jdbc-odbc bridge driver
     Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
     // Enable logging
     DriverManager.setLogWriter(new PrintWriter((System.err)));
     System.out.println("Getting Connection");
     Connection conn = DriverManager.getConnection(dbURL, "user", "password");
     SQLWarning warn = conn.getWarnings();
     while (warn != null) {
       System.out.println("SQLState: " + warn.getSQLState());
       System.out.println("Message:  " + warn.getMessage());
       System.out.println("Vendor:   " + warn.getErrorCode());
       System.out.println("");
       warn = warn.getNextWarning();
     }
     conn.close();
   } catch (ClassNotFoundException e) {
     System.out.println("Can"t load driver " + e);
   } catch (SQLException e) {
     System.out.println("Database access failed " + e);
   }
 }

} 


 </source>



Connection: nativeSQL(String sql)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   Connection conn = getConnection();
   conn.setAutoCommit(false);
   Statement st = conn.createStatement();
   st.executeUpdate("create table survey (id int,myURL CHAR);");
   String str = conn.nativeSQL("insert into survey(id) values(02)");
   System.out.println(str);
   
   conn.rumit();    
   st.close();
   conn.close();
 }
 private static Connection getConnection() throws Exception {
   Class.forName("org.hsqldb.jdbcDriver");
   String url = "jdbc:hsqldb:mem:data/tutorial";
   return DriverManager.getConnection(url, "sa", "");
 }

} 


 </source>



Connection: prepareCall(String sql)

   <source lang="java">

import java.sql.CallableStatement; import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   CallableStatement cs = conn.prepareCall("{call StoreProcedureName}");
   ResultSet rs = cs.executeQuery();
   while (rs.next()) {
     System.out.println("Defunct user: " + rs.getString("user"));
   }
 }
 static Connection conn;
 static Statement st;
 public static void setup() {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection: prepareStatement(String sql)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql.SQLException; public class Main { 

 public static void main(String[] args) throws Exception {
   try {
     String url = "jdbc:odbc:databaseName";
     String driver = "sun.jdbc.odbc.JdbcOdbcDriver";
     String user = "guest";
     String password = "guest";
     Class.forName(driver);
     Connection connection = DriverManager.getConnection(url,user, password);
     String changeLastName = "UPDATE authors SET lastname = ? WHERE authid = ?";
     PreparedStatement updateLastName = connection.prepareStatement(changeLastName);
     updateLastName.setString(1, "Martin"); // Set lastname placeholder value
     updateLastName.setInt(2, 4); // Set author ID placeholder value
     int rowsUpdated = updateLastName.executeUpdate(); // execute the update
     System.out.println("Rows affected: " + rowsUpdated);
     connection.close();
   } catch (ClassNotFoundException cnfe) {
     System.err.println(cnfe);
   } catch (SQLException sqle) {
     System.err.println(sqle);
   }
 }

} 


 </source>



Connection: rollback()

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   Connection conn = getHSQLConnection();
   
   conn.setAutoCommit(false);
   Statement st = conn.createStatement();
   try {
     st.executeUpdate("create table survey (id int,name varchar(30));");
     st.executeUpdate("insert into survey (id,name ) values (1,"nameValue")");
     st.executeUpdate("insert into survey (id,name ) values (2,"nameValue")");
      // commits all the transactions
      conn.rumit();
   }
   catch (Exception e){
      //cancel (roll back) all the transactions
      conn.rollback();
      // to see what went wrong
      e.printStackTrace();
   }
   
   
   
   st = conn.createStatement();
   ResultSet rs = st.executeQuery("SELECT * FROM survey");
   outputResultSet(rs);
   rs.close();
   st.close();
   conn.close();
 }
 private static void outputResultSet(ResultSet rs) throws Exception {
   ResultSetMetaData rsMetaData = rs.getMetaData();
   int numberOfColumns = rsMetaData.getColumnCount();
   for (int i = 1; i < numberOfColumns + 1; i++) {
     String columnName = rsMetaData.getColumnName(i);
     System.out.print(columnName + "   ");
   }
   System.out.println();
   System.out.println("----------------------");
   while (rs.next()) {
     for (int i = 1; i < numberOfColumns + 1; i++) {
       System.out.print(rs.getString(i) + "   ");
     }
     System.out.println();
   }
 }
 private static Connection getHSQLConnection() throws Exception {
   Class.forName("org.hsqldb.jdbcDriver");
   String url = "jdbc:hsqldb:mem:data/tutorial";
   return DriverManager.getConnection(url, "sa", "");
 }

} 


 </source>



Connection: rollback(Savepoint savepoint)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Savepoint; import java.sql.Statement; public class MainClass { 

 public static void main(String[] args) {
   Connection connection = null;
   Statement statement = null;
   try {
     Class.forName("org.hsqldb.jdbcDriver").newInstance();
     String url = "jdbc:hsqldb:hsqldb\\demoDatabase";
     connection = DriverManager.getConnection(url, "username", "password");
     connection.setAutoCommit(false);
     statement = connection.createStatement();
     String update1 = "UPDATE employees SET email = "a@b.ru" WHERE email = "a@a.ru"";
     statement.executeUpdate(update1);
     Savepoint savepoint1 = connection.setSavepoint("savepoint1");
     String update2 = "UPDATE employees SET email = "b@b.ru" WHERE email = "b@c.ru"";
     statement.executeUpdate(update2);
     Savepoint savepoint2 = connection.setSavepoint("savepoint2");
     String update3 = "UPDATE employees SET email = "c@c.ru" WHERE email = "c@d.ru"";
     statement.executeUpdate(update3);
     Savepoint savepoint3 = connection.setSavepoint("savepoint3");
     String update4 = "UPDATE employees SET email = "d@d.ru" WHERE email = "d@e.ru"";
     statement.executeUpdate(update4);
     Savepoint savepoint4 = connection.setSavepoint("savepoint4");
     String update5 = "UPDATE employees SET email = "e@e.ru" WHERE email = "e@f.ru"";
     statement.executeUpdate(update5);
     Savepoint savepoint5 = connection.setSavepoint("savepoint5");
     connection.rollback(savepoint3);
     connection.rumit();
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     if (statement != null) {
       try {
         statement.close();
       } catch (SQLException e) {
       } // nothing we can do
     }
     if (connection != null) {
       try {
         connection.close();
       } catch (SQLException e) {
       } // nothing we can do
     }
   }
 }

} 


 </source>



Connection: setAutoCommit(boolean autoCommit)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.ResultSetMetaData; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   Connection conn = getHSQLConnection();
   conn.setAutoCommit(false);
   Statement st = conn.createStatement();
   st.executeUpdate("create table survey (id int,name varchar(30));");
   st.executeUpdate("insert into survey (id,name ) values (1,"nameValue")");
   st = conn.createStatement();
   ResultSet rs = st.executeQuery("SELECT * FROM survey");
   outputResultSet(rs);
   rs.close();
   st.close();
   conn.close();
 }
 private static void outputResultSet(ResultSet rs) throws Exception {
   ResultSetMetaData rsMetaData = rs.getMetaData();
   int numberOfColumns = rsMetaData.getColumnCount();
   for (int i = 1; i < numberOfColumns + 1; i++) {
     String columnName = rsMetaData.getColumnName(i);
     System.out.print(columnName + "   ");
   }
   while (rs.next()) {
     for (int i = 1; i < numberOfColumns + 1; i++) {
       System.out.print(rs.getString(i) + "   ");
     }
     System.out.println();
   }
 }
 private static Connection getHSQLConnection() throws Exception {
   Class.forName("org.hsqldb.jdbcDriver");
   String url = "jdbc:hsqldb:mem:data/tutorial";
   DriverManager.setLoginTimeout(60); // fail after 60 seconds
   return DriverManager.getConnection(url, "sa", "");
 }

} 


 </source>



Connection: setSavepoint(String name)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; import java.sql.Savepoint; import java.sql.Statement; public class MainClass { 

 public static void main(String[] args) {
   Connection connection = null;
   Statement statement = null;
   try {
     Class.forName("org.hsqldb.jdbcDriver").newInstance();
     String url = "jdbc:hsqldb:hsqldb\\demoDatabase";
     connection = DriverManager.getConnection(url, "username", "password");
     connection.setAutoCommit(false);
     statement = connection.createStatement();
     String update1 = "UPDATE employees SET email = "a@b.ru" WHERE email = "a@a.ru"";
     statement.executeUpdate(update1);
     Savepoint savepoint1 = connection.setSavepoint("savepoint1");
     String update2 = "UPDATE employees SET email = "b@b.ru" WHERE email = "b@c.ru"";
     statement.executeUpdate(update2);
     Savepoint savepoint2 = connection.setSavepoint("savepoint2");
     String update3 = "UPDATE employees SET email = "c@c.ru" WHERE email = "c@d.ru"";
     statement.executeUpdate(update3);
     Savepoint savepoint3 = connection.setSavepoint("savepoint3");
     String update4 = "UPDATE employees SET email = "d@d.ru" WHERE email = "d@e.ru"";
     statement.executeUpdate(update4);
     Savepoint savepoint4 = connection.setSavepoint("savepoint4");
     String update5 = "UPDATE employees SET email = "e@e.ru" WHERE email = "e@f.ru"";
     statement.executeUpdate(update5);
     Savepoint savepoint5 = connection.setSavepoint("savepoint5");
     connection.rollback(savepoint3);
     connection.rumit();
   } catch (Exception e) {
     e.printStackTrace();
   } finally {
     if (statement != null) {
       try {
         statement.close();
       } catch (SQLException e) {
       } // nothing we can do
     }
     if (connection != null) {
       try {
         connection.close();
       } catch (SQLException e) {
       } // nothing we can do
     }
   }
 }

} 


 </source>



Connection: setTransactionIsolation(int level)

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection.TRANSACTION_NONE

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection.TRANSACTION_READ_COMMITTED

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection.TRANSACTION_READ_UNCOMMITTED

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection.TRANSACTION_REPEATABLE_READ

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>



Connection.TRANSACTION_SERIALIZABLE

   <source lang="java">

import java.sql.Connection; import java.sql.DriverManager; import java.sql.Statement; public class Main { 

 public static void main(String[] args) throws Exception {
   int tx = conn.getMetaData().getDefaultTransactionIsolation();
   String txtxt=null;
   switch(tx) {
     case Connection.TRANSACTION_NONE :
       txtxt = "TRANSACTION_NONE"; break;
     case Connection.TRANSACTION_READ_COMMITTED :
       txtxt = "TRANSACTION_READ_COMMITTED"; break;
     case Connection.TRANSACTION_READ_UNCOMMITTED :
       txtxt = "TRANSACTION_READ_UNCOMMITTED"; break;
     case Connection.TRANSACTION_REPEATABLE_READ :
       txtxt = "TRANSACTION_REPEATABLE_READ"; break;
         case Connection.TRANSACTION_SERIALIZABLE :
       txtxt = "TRANSACTION_SERIALIZABLE"; break;
     default:
       txtxt = "UNKNOWN!!";
   }
   System.out.println(txtxt);
   conn.setTransactionIsolation(tx);
   System.out.println("Done");
   conn.setTransactionIsolation(Connection.TRANSACTION_REPEATABLE_READ);
   System.out.println("TX is now " + conn.getTransactionIsolation());
 }
 static Connection conn;
 static Statement st;
 static {
   try {
     // Step 1: Load the JDBC driver.
     Class.forName("org.hsqldb.jdbcDriver");
     System.out.println("Driver Loaded.");
     // Step 2: Establish the connection to the database.
     String url = "jdbc:hsqldb:data/tutorial";
     conn = DriverManager.getConnection(url, "sa", "");
     System.out.println("Got Connection.");
     st = conn.createStatement();
   } catch (Exception e) {
     System.err.println("Got an exception! ");
     e.printStackTrace();
     System.exit(0);
   }
 }

} 


 </source>
Источник — «http://jexp.ru/index.php?title=Java_by_API/java.sql/Connection&oldid=2433»