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2010-06-01T05:05:58Z

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в 17:44, 31 мая 2010

2010-05-31T17:44:27Z

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== Cancelling Updates to an Updatable 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);
Statement stmt = connection.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,
ResultSet.CONCUR_UPDATABLE);
ResultSet resultSet = stmt.executeQuery("SELECT * FROM my_table");
// Move cursor to the row to update
resultSet.first();
// Update the value of column col_string on that row
resultSet.updateString("col_string", "new data");
// Discard the update to the row
resultSet.cancelRowUpdates();
}
}</source>



== Cancel Updates to an Updatable ResultSet ==

<p>You cannot cancel updates after you have called updateRow().</p>



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");

ResultSet rs = st.executeQuery("SELECT * FROM survey");
// Move cursor to the row to update
rs.first();
// Update the value of column column_1 on that row
rs.updateString("name", "new data");
// Discard the update to the row
rs.cancelRowUpdates();
rs.close();
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>



== Create an Updatable ResultSet ==



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
st.executeUpdate("create table survey (pk_column int,name varchar(30));");
st.executeUpdate("insert into survey (pk_column,name ) values (1,"nameValue")");
st.executeUpdate("insert into survey (pk_column,name ) values (2,null)");
st.executeUpdate("insert into survey (pk_column,name ) values (3,"Tom")");
// Primary key pk_column must be specified
// so that the result set is updatable
ResultSet rs = st.executeQuery("SELECT pk_column FROM survey");
rs.close();
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>



== Delete a Row from a Database Table Using an Updatable ResultSet ==



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");
ResultSet rs = st.executeQuery("SELECT id,name FROM survey");
// Delete the first row
rs.first();
rs.deleteRow();
rs.close();
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>



== Determine if a Database Supports Updatable ResultSets ==



<source lang="java">
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.ResultSet;
public class Main {
public static void main(String[] args) throws Exception {
Connection conn = getConnection();
DatabaseMetaData dbmd = conn.getMetaData();
if (dbmd.supportsResultSetConcurrency(ResultSet.TYPE_FORWARD_ONLY,
ResultSet.CONCUR_UPDATABLE)) {
System.out.println("Updatable ResultSets are supported");
}
else {
System.out.println("Updatable ResultSets are not supported");
}

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>



== Determine if a ResultSet is Updatable ==



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");

ResultSet resultSet = st.executeQuery("SELECT * FROM survey");
// get concurrency of the ResultSet object
int concurrency = resultSet.getConcurrency();
if (concurrency == ResultSet.CONCUR_UPDATABLE) {
System.out.println("ResultSet is updatable");
}
else {
System.out.println("ResultSet is not updatable");
}
resultSet.close();
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>



== Insert a Row into a Database Table Using an Updatable ResultSet ==



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");

ResultSet rs = st.executeQuery("SELECT id,name FROM survey");
rs.moveToInsertRow();
rs.updateString("id", "66");
rs.updateString("name", "H F");
// Insert the row
rs.insertRow();

rs.close();
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>



== Refresh a Row in an Updatable ResultSet ==



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");
ResultSet rs = st.executeQuery("SELECT id,name FROM survey");
// Use the result set
// Retrieve the current values of the row from the database
rs.refreshRow();

rs.close();
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>



== Update a Row in a Database Table Using an Updatable Result Set ==

<p>Updating the current row of an updatable result set involves calling the ResultSet.updateXXX() methods followed by a call to updateRow():</p>



<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[] args) throws Exception {
Connection conn = getConnection();
Statement st = conn
.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
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,null)");
st.executeUpdate("insert into survey (id,name ) values (3,"Tom")");

ResultSet rs = st.executeQuery("SELECT * FROM survey");
// Move cursor to the row to update
rs.first();
// Update the value of column column_1 on that row
rs.updateString("name", "new data");
// Update the row; if autocommit is enabled,
// update is committed
rs.updateRow();
rs.close();
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>

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Admin: 1 версия

в 17:44, 31 мая 2010