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2010-06-01T05:06:19Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Connection Object ==

<p>The Connection object has the following capabilities:</p>
<OL><LI>Creates SQL statements</LI><LI>Executes SQL queries, inserts, updates, and deletes</LI><LI>Handles commits and rollbacks</LI><LI>Provides metadata regarding the database connection</LI></OL>
<p>By default, a Connection object is in autocommit mode,
which means it automatically commits changes after executing each statement.</p>

== Connection Object Requirements ==

ParameterDescriptiondriverNameJDBC driverdbURLDatabase URL (uniquely identifies a database)dbUsernameDatabase usernamedbPasswordDatabase user password

== Connection Properties: Pass additional properties using java.util.Properties: ==



<source lang="java">
Properties properties = new java.util.Properties();
properties.put("user", "root");properties.put("password","rootp");
properties.put("useUnicode","true");
properties.put("characterEncoding","utf8");
String databaseURL = "jdbc:mysql://localhost/yourDB";
Connection conn = DriverManager.getConnection(databaseURL, properties);</source>



== Connection"s Method to Print Native 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>



== Passing "user" and "password" Parameters as a java.util.Properties Object to Connection object ==



<source lang="java">
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
public class Main {
public static Connection getConnection(String dbURL, String user, String password)
throws SQLException, ClassNotFoundException {
Class.forName("com.mysql.jdbc.Driver");
Properties props = new Properties();
props.put("user", user);
props.put("password", password);
props.put("autoReconnect", "true");
return DriverManager.getConnection(dbURL, props);
}
public static void main(String[] args) {
Connection conn = null;
try {
conn = getConnection("jdbc:mysql://localhost/empDB", "root", "pass");
} catch (Exception ex) {
System.out.println("SQLException: " + ex.getMessage());
}
}
}</source>



== Test to See if Your Connection is Alive ==

<OL><LI>For Oracle database: you may use the Connection object with query of "select 1 from dual"; if the query returns the result, then it is a valid Connection object.</LI><LI>For MySQL database: you may use the Connection object with query of "select 1"; if the query returns the result, then it is a valid Connection object.</LI></OL>

== Vendor URL Formats ==



<source lang="java">
Vendor Driver Name URL Sample
Oracle 8i oracle.jdbc.driver.OracleDriver jdbc:oracle:thin:@localhost:1521:yourDatabase
Oracle 9i oracle.jdbc.driver.OracleDriver jdbc:oracle:thin:@localhost:1521:yourDatabase
MySQL org.gjt.mm.mysql.Driver jdbc:mysql://localhost/yourDatabase
Microsoft Access sun.jdbc.odbc.JdbcOdbcDriver jdbc:odbc:scorpian

Sybase(jConnect 5.2) com.sybase.jdbc2.jdbc.SybDriver jdbc:sybase:Tds:scorpian:2638

MS SQL Server 2000 com.microsoft.jdbc. sqlserver.SQLServerDriver jdbc:microsoft:sqlserver://localhost:1433
MS SQL Server 2000 weblogic.jdbc.mssqlserver4.Driver jdbc:weblogic:mssqlserver4:database@ localhost:port
IBM DB2 COM.ibm.db2.jdbc.net.DB2Connection jdbc:db2://localhost:6789/yourDatabase</source>

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Admin: 1 версия

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