Admin: 1 версия

2010-06-01T05:06:28Z

1 версия

в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Change the fetch size on the result set ==



<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);
// Get the fetch size of a statement
Statement stmt = connection.createStatement ();
int fetchSize = stmt.getFetchSize();
// Set the fetch size on the statement
stmt.setFetchSize(100);
// Create a result set
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Change the fetch size on the result set
resultSet.setFetchSize(100);
}
}</source>



== Create a result set ==



<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);
// Get the fetch size of a statement
Statement stmt = connection.createStatement ();
int fetchSize = stmt.getFetchSize();
// Set the fetch size on the statement
stmt.setFetchSize(100);
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Change the fetch size on the result set
resultSet.setFetchSize(100);
}
}</source>



== Creating a Database Table called my_table with one column, col_string, which holds strings. ==



<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);
Statement stmt = connection.createStatement();

// Create table called my_table
String sql = "CREATE TABLE my_table(col_string VARCHAR(254))";
stmt.executeUpdate(sql);
}
}</source>



== Deleting a Database Table called my_table from a database. ==



<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);
Statement stmt = connection.createStatement();

stmt.executeUpdate("DROP TABLE my_table");
}
}</source>



== Deleting a Row from a Database Table ==



<source lang="java">
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
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);
Statement stmt = connection.createStatement();
String sql = "DELETE FROM my_table WHERE col_string="a string"";
int deleteCount = stmt.executeUpdate(sql);
sql = "DELETE FROM my_table WHERE col_string=?";
PreparedStatement pstmt = connection.prepareStatement(sql);
pstmt.setString(1, "a string");
deleteCount = pstmt.executeUpdate();
}
}</source>



== Get the fetch size of a statement ==



<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);
// Get the fetch size of a statement
Statement stmt = connection.createStatement ();
int fetchSize = stmt.getFetchSize();
// Set the fetch size on the statement
stmt.setFetchSize(100);
// Create a result set
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Change the fetch size on the result set
resultSet.setFetchSize(100);
}
}</source>



== Getting Column Names from a database table in Java ==



<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[] argv) throws Exception {
String driver = "com.mysql.jdbc.Driver";
String user = "root";
String pass = "root";
Class.forName(driver);
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", user, pass);
Statement st = con.createStatement();
ResultSet rs = st.executeQuery("SELECT * FROM employee6");
ResultSetMetaData md = rs.getMetaData();
int col = md.getColumnCount();
System.out.println("Number of Column : " + col);
for (int i = 1; i <= col; i++) {
String col_name = md.getColumnName(i);
System.out.println(col_name);
}
}
}</source>



== Inserting a Row into a Database Table ==



<source lang="java">
import java.sql.Connection;
import java.sql.DriverManager;
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);
Statement stmt = connection.createStatement();
String sql = "INSERT INTO my_table (col_string) VALUES("a string")";
stmt.executeUpdate(sql);
}
}</source>



== Inserting a Row into a Database Table Using a Prepared Statement ==



<source lang="java">
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
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);
String sql = "INSERT INTO my_table (col_string) VALUES(?)";
PreparedStatement pstmt = connection.prepareStatement(sql);
// Insert 10 rows
for (int i = 0; i < 10; i++) {
// Set the value
pstmt.setString(1, "row " + i);
// Insert the row
pstmt.executeUpdate();
}
}
}</source>



== Retrieve a rowcount from a ResultSet ==



<source lang="java">
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
Connection conn = null;
Statement s = conn.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
ResultSet.CONCUR_READ_ONLY);
ResultSet r = s
.executeQuery("SELECT * FROM employee");
r.last();
int count = r.getRow();
r.beforeFirst();
}
}</source>



== Retrieving All Rows from a Database Table ==



<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 driver = "com.mysql.jdbc.Driver";
String user = "root";
String pass = "root";
Class.forName(driver).newInstance();
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial", user, pass);
Statement st = con.createStatement();
ResultSet res = st.executeQuery("SELECT * FROM emp");
while (res.next()) {
int i = res.getInt("ID");
String s = res.getString("name");
System.out.println(i + "\t\t" + s);
}
con.close();
}
}</source>



== Set the fetch size on the statement ==



<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);
// Get the fetch size of a statement
Statement stmt = connection.createStatement ();
int fetchSize = stmt.getFetchSize();
// Set the fetch size on the statement
stmt.setFetchSize(100);
// Create a result set
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Change the fetch size on the result set
resultSet.setFetchSize(100);
}
}</source>



== Setting the Number of Rows to Prefetch When Executing a SQL Query ==



<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);
Statement stmt = connection.createStatement ();
int fetchSize = stmt.getFetchSize();
// Set the fetch size on the statement
stmt.setFetchSize(100);
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Change the fetch size on the result set
resultSet.setFetchSize(100);
}
}</source>



== Statement Batch Update ==



<source lang="java">
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] argv) throws Exception {
Class.forName("com.mysql.jdbc.Driver");
Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/jdbctutorial",
"root", "root");
con.setAutoCommit(false);
String table1 = "INSERT emp_sal VALUES("v",1200)";
String table2 = "DELETE FROM movies WHERE title = "r"";
Statement st = con.createStatement();
st.addBatch(table1);
st.addBatch(table2);
int count[] = st.executeBatch();
con.rumit();
con.close();
System.out.println("Successfully!");
}
}</source>

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Admin: 1 версия

в 17:44, 31 мая 2010