JDBC Series: (2) Execute SQL statements using statement

interface for executing SQL statements

Interface	function
Statement interface	Used to execute a static SQL statement
PreparedStatement interface	Used to execute precompiled SQL statements
CallableStatement interface	SQL statement for execution of stored procedures (call XXX)

1. Executing DDL statements

package com.rk.db.b_statement;
import java.sql.drivermanager;
import java.sql.connection;
import java.sql.sqlexception;

import java.sql.statement; /**  *  Execute DDL statements with statement (CREATE TABLE)  *  @author  rk  *  */public class 
		Demo01 {static//Static code snippet {try {//1. Driver registration Program Class.forName ("Com.mysql.jdbc.Driver");
			} catch  (Classnotfoundexception e) {e.printstacktrace ();
		Throw new runtimeexception (e);
		}} public static void main (String[] args) {connection conn = null;
		
		statement stmt = null;
		string url =  "Jdbc:mysql://localhost:3306/testdb";
		string user =  "Root";
		
		string password =  "Root";
			
			try {//2. Get Connection Object Conn = drivermanager.getconnection (Url, user, password);
			
			3. Create statement stmt = conn.createstatement (); 4. Prepare SQL String sql =  "Create table t_persons (id int primary key auto_
			
			Increment, username varchar (+),  pwd varchar (20)) ";
			
			5. Send SQL statement, execute SQL statement, get return result int count = stmt.executeupdate (SQL); 6. Output System.out.println ("affects" +count+ "line!)
		");//affects 0 rows!
		} catch  (Sqlexception e) {e.printstacktrace ();
			} finally {//7. Close connection (order: Open first close) closequietly (stmt);
		closequietly (conn); }}/**  *  quiet close  */private static void closequietly (AUTOCLOSEABLE AC) {if (
			Ac != null) {try {ac.close ();
			} catch  (Exception e) {e.printstacktrace (); }
		}
	}
}

2. Executing DML statements

package com.rk.db.b_statement;
import java.sql.drivermanager;
import java.sql.connection;
import java.sql.sqlexception;

import java.sql.statement;
	/**  *  using statement to execute DML statements  *  @author  rk  *  */public class demo02 {
		static {try {//1. Driver registration Program Class.forName ("Com.mysql.jdbc.Driver");
		} catch  (Classnotfoundexception e) {throw new runtimeexception (e);
		}} public static void main (String[] args) {connection conn = null;
		
		statement stmt = null;
		string url =  "Jdbc:mysql://localhost:3306/testdb";
		string user =  "Root";
		
		string password =  "Root";
			
			try {//2. Get Connection Object Conn = drivermanager.getconnection (Url, user, password);
			
			3. Create statement stmt = conn.createstatement (); 4. Prepare SQL string sql =  "INSERT&NBsp;into t_persons (username,pwd)  values (' Earth Man ', ' 123456 ');//Add//string sql =  "UPDATE  t_persons set username= ' Martian '  where id=1 ';//Modify//string sql =  "DELETE  from t_persons where id=1 ";//delete//5. Send SQL statement, execute SQL statement, get return result int count = stmt.
			
			executeupdate (SQL); 6. Output System.out.println ("affects" +count+ "line!)
		");//affects 1 rows!
		} catch  (Sqlexception e) {e.printstacktrace ();
			} finally {closequietly (stmt);
		closequietly (conn); }}/**  *  quiet off  */private static void closequietly (AUTOCLOSEABLE AC) {if (a
			C != null) {try {ac.close ();
			} catch  (Exception e) {e.printstacktrace (); }
		}
	}
}

3. Execute DQL Statement

package com.rk.db.b_statement;
import java.sql.drivermanager;
import java.sql.connection;
import java.sql.sqlexception;
import java.sql.statement;

import java.sql.resultset; /**  *  Execute DQL statement using statement (query operation)  *  @author  rk  *  */public class 
		Demo03 {static {try {//1. Driver registration Program Class.forName ("Com.mysql.jdbc.Driver");
		} catch  (Classnotfoundexception e) {throw new runtimeexception (e);
		}} public static void main (String[] args) {connection conn = null;
		statement stmt = null;
		
		resultset rs = null;
		string url =  "Jdbc:mysql://localhost:3306/testdb";
		string user =  "Root";
		
		string password =  "Root";
			
			try {//2. Get Connection Object Conn = drivermanager.getconnection (Url, user, password); 3. Create statement stmt = conn.Createstatement ();
			
			4. Prepare SQL string sql =  "Select * from t_persons";
			
			5. Send SQL statement, execute SQL statement, get return result rs = stmt.executequery (SQL);
				6. Output while (Rs.next ()) {Int id = rs.getint ("id");
				String username = rs.getstring ("UserName");
				String pwd = rs.getstring ("pwd");
			System.out.println (id +  "\ t"  + userName +  "\ T"  + pwd);
		}} catch  (Sqlexception e) {e.printstacktrace ();
			} finally {closequietly (RS);
			closequietly (stmt);
		closequietly (conn); }}/**  *  quiet off  */private static void closequietly (AUTOCLOSEABLE AC) {if (a
			C != null) {try {ac.close ();
			} catch  (Exception e) {e.printstacktrace (); }
		}
	}
}

4. Mind Mapping

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JDBC Series: (2) Execute SQL statements using statement