To update the contents of the ResultSet you need to create a statement by passing the ResultSet type updatable, as:
//Creating a Statement object Statement stmt = con.createStatement(ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE);
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就像getXXX()和setXXX()方法一樣，ResultSet接口還提供了updateXXX()方法來更新結(jié)果集中行的內(nèi)容。
這些方法接受表示要更新的行的索引或列標(biāo)簽的字符串值。
請(qǐng)注意，如果您需要更新ResultSet的內(nèi)容，表格應(yīng)該有一個(gè)主鍵。
示例
假設(shè)我們有一個(gè)名為Employees的表，其中有5條記錄，如下所示：
+----+---------+--------+----------------+ | Id | Name | Salary | Location | +----+---------+--------+----------------+ | 1 | Amit | 3000 | Hyderabad | | 2 | Kalyan | 4000 | Vishakhapatnam | | 3 | Renuka | 6000 | Delhi | | 4 | Archana | 9000 | Mumbai | | 5 | Sumith | 11000 | Hyderabad | +----+---------+--------+----------------+
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以下示例演示了如何更新結(jié)果集的內(nèi)容：
import java.sql.*;
public class ResultSetExample {
public static void main(String[] args) throws Exception {
//Registering the Driver
DriverManager.registerDriver(new com.mysql.jdbc.Driver());
//Getting the connection
String mysqlUrl = "jdbc:mysql://localhost/TestDB";
Connection con = DriverManager.getConnection(mysqlUrl, "root", "password");
System.out.println("Connection established......");
//Creating a Statement object
Statement stmt = con.createStatement(
ResultSet.TYPE_SCROLL_SENSITIVE, ResultSet.CONCUR_UPDATABLE);
//Retrieving the data
ResultSet rs = stmt.executeQuery("select * from Employees");
//Printing the contents of the table
System.out.println("Contents of the table: ");
printRs(rs);
//Moving the pointer to the starting point in the ResultSet
rs.beforeFirst();
//Updating the salary of each employee by 5000
while(rs.next()){
//Retrieve by column name
int newSal = rs.getInt("Salary") + 5000;
rs.updateInt( "Salary", newSal );
rs.updateRow();
}
System.out.println("Contents of the ResultSet after increasing salaries");
printRs(rs);
// Set position to second record first
rs.beforeFirst();
rs.absolute(2);
System.out.println("Record we need to delete: ");
System.out.print("ID: " + rs.getInt("id"));
System.out.print(", Salary: " + rs.getInt("Salary"));
System.out.print(", Name: " + rs.getString("Name"));
System.out.println(", Location: " + rs.getString("Location"));
System.out.println(" ");
//Deleting the row
rs.deleteRow();
System.out.println("Contents of the ResultSet after deleting one records...");
printRs(rs);
System.out.println("Goodbye!");
}
public static void printRs(ResultSet rs) throws SQLException{
//Ensure we start with first row
rs.beforeFirst();
while(rs.next()){
System.out.print("ID: " + rs.getInt("id"));
System.out.print(", Salary: " + rs.getInt("Salary"));
System.out.print(", Name: " + rs.getString("Name"));
System.out.println(", Location: " + rs.getString("Location"));
}
System.out.println();
}
}
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輸出
Connection established...... Contents of the table: ID: 1, Salary: 3000, Name: Amit, Location: Hyderabad ID: 2, Salary: 4000, Name: Kalyan, Location: Vishakhapatnam ID: 3, Salary: 6000, Name: Renuka, Location: Delhi ID: 4, Salary: 9000, Name: Archana, Location: Mumbai ID: 5, Salary: 11000, Name: Sumith, Location: Hyderabad Conetnets of the resultset after increaing salaries ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam ID: 3, Salary: 11000, Name: Renuka, Location: Delhi ID: 4, Salary: 14000, Name: Archana, Location: Mumbai ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad Record we need to delete: ID: 2, Salary: 9000, Name: Kalyan, Location: Vishakhapatnam Contents of the resultset after deleting one records... ID: 1, Salary: 8000, Name: Amit, Location: Hyderabad ID: 3, Salary: 11000, Name: Renuka, Location: Delhi ID: 4, Salary: 14000, Name: Archana, Location: Mumbai ID: 5, Salary: 16000, Name: Sumith, Location: Hyderabad Goodbye!
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