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MySQL – Update View

Table of content

The MySQL UPDATE statement is used on various database objects to update the existing data in them. This is a DML (Data Manipulation language) command.

We need to be careful while using the UPDATE statement as it can modify all the records in an object, if not selected beforehand. To avoid losing or re-inserting correct data, we use clauses to filter the records that need to be updated. This way, we can update either a single row or multiple rows selectively.

MySQL UPDATE View Statement

In MySQL, a view is a database object that can contain rows (all or selected) from an existing table. It can be created from one or many tables which depends on the provided SQL query to create a view.

There is no direct statement to update a MySQL view. We use the UPDATE statement to modify all or selective records in a view. The results are reflected back in the original table as well.

Syntax

The basic syntax of the UPDATE query with a WHERE clause is as follows −

UPDATE view_name
SET column1 = value1, column2 = value2...., columnN = valueN
WHERE [condition];

Note: We can combine N number of conditions using the AND or the OR operators.

Example

First of all, let us create a table with the name CUSTOMERS using the following query −

CREATE TABLE CUSTOMERS(
   ID int NOT NULL,
   NAME varchar(20) NOT NULL,
   AGE int NOT NULL,
   ADDRESS varchar(25),
   SALARY decimal(18, 2),
   PRIMARY KEY (ID)
);

Now, we are inserting some records into this table using the INSERT statement as follows −

INSERT INTO CUSTOMERS VALUES 
(1, ''Ramesh'', ''32'', ''Ahmedabad'', 2000),
(2, ''Khilan'', ''25'', ''Delhi'', 1500),
(3, ''Kaushik'', ''23'', ''Kota'', 2500),
(4, ''Chaitali'', ''26'', ''Mumbai'', 6500),
(5, ''Hardik'',''27'', ''Bhopal'', 8500),
(6, ''Komal'', ''22'', ''MP'', 9000),
(7, ''Muffy'', ''24'', ''Indore'', 5500);

Creating a view −

Following query creates a view based on the above created table −

CREATE VIEW CUSTOMERS_VIEW AS SELECT * FROM CUSTOMERS;

Using the following query, we can verify the contents of a view −

SELECT * FROM CUSTOMERS_VIEW;

The view will be displayed as follows −

ID NAME AGE ADDRESS SALARY
1 Ramesh 32 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
3 Kaushik 23 Kota 2000.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

Updating this view −

Now, through the view we created, we are trying to update the age of Ramesh to 35 in the original CUSTOMERS table, using the following query −

UPDATE CUSTOMERS_VIEW SET AGE = 35 WHERE name = ''Ramesh

This will ultimately update the base table CUSTOMERS and the same would reflect in the view itself.

Verification

Using a SELECT query, we can retrieve the actual CUSTOMERS table containing following records −

ID NAME AGE ADDRESS SALARY
1 Ramesh 35 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
3 Kaushik 23 Kota 2000.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

Updating Multiple Rows and Columns

In MySQL, we can update multiple rows and columns of a table using the UPDATE statement. To update multiple rows, specify the condition in a WHERE clause such that only the required rows would satisfy it.

To update multiple columns, set the new values to all the columns that need to be updated. In this case, using the WHERE clause would narrow down the records of the table and not using the clause would change all the values in these columns.

Syntax

Following is the syntax to update multiple rows and columns −

UPDATE table_name
SET column_name1 = new_value, column_name2 = new_value...
WHERE condition(s)

Example

In the following query, we are trying to modify the NAME and AGE column values in the CUSTOMERS table for WHERE ID = 3:

UPDATE CUSTOMERS_VIEW 
SET NAME = ''Kaushik'', AGE = 24
WHERE ID = 3;

Verification

Using the SELECT query, we can retrieve the CUSTOMERS table with following records −

ID NAME AGE ADDRESS SALARY
1 Ramesh 35 Ahmedabad 2000.00
2 Khilan 25 Delhi 1500.00
3 Kaushik 24 Kota 2000.00
4 Chaitali 25 Mumbai 6500.00
5 Hardik 27 Bhopal 8500.00
6 Komal 22 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

Example

If we want to modify all the records of AGE column in the CUSTOMERS table, we can use the following query −

UPDATE CUSTOMERS_VIEW SET AGE = 24;

Output

This query produces the following output −

Query OK, 5 rows affected (0.01 sec)
Rows matched: 7  Changed: 5  Warnings: 0

Verification

Using the SELECT query, we display the CUSTOMERS table with following records −

ID NAME AGE ADDRESS SALARY
1 Ramesh 24 Ahmedabad 2000.00
2 Khilan 24 Delhi 1500.00
3 Kaushik 24 Kota 2000.00
4 Chaitali 24 Mumbai 6500.00
5 Hardik 24 Bhopal 8500.00
6 Komal 24 Hyderabad 4500.00
7 Muffy 24 Indore 10000.00

Updated a View Using a Client Program

We have learned how to update a view using the SQL UPDATE query. In addition to it, we can also perform the update operation on a view using another client program.

Syntax

To update a view in a MySQL Database through a PHP program, we need to execute the UPDATE or ALTER statement using the mysqli function named query() as follows −

$sql = "ALTER VIEW first_view AS SELECT tutorial_id, tutorial_title, tutorial_author FROM clone_table WHERE tutorial_id = 101";
$mysqli->query($sql);

To update a view in a MySQL Database through a JavaScript program, we need to execute the UPDATE or ALTER statement using the query() function of mysql2 library as follows −

sql = "UPDATE CUSTOMERS_VIEW SET AGE = 35 WHERE name = ''Ramesh''";
con.query(sql);

To update a view in a MySQL Database through a Java program, we need to execute the UPDATE or ALTER statement using the JDBC function executeUpdate() as follows −

String sql = "ALTER VIEW first_view AS select tutorial_id, tutorial_title, tutorial_author from tutorials_tbl where tutorial_id = 1";
st.execute(sql);

To update a view in a MySQL Database through a python program, we need to execute the UPDATE or ALTER statement using the execute() function of the MySQL Connector/Python as follows −

update_view_query = "UPDATE tutorial_view SET tutorial_title = ''New Title'' WHERE tutorial_id = 2"
cursorObj.execute(update_view_query)

Example

Following are the programs −

$dbhost = ''localhost
$dbuser = ''root
$dbpass = ''password
$dbname = ''TUTORIALS
$mysqli = new mysqli($dbhost, $dbuser, $dbpass, $dbname);

if ($mysqli->connect_errno) {
    printf("Connect failed: %s
", $mysqli->connect_error);
    exit();
}
// printf(''Connected successfully.
'');

// A view can be updated by using the CREATE OR REPLACE;
$sql = "ALTER VIEW first_view AS SELECT tutorial_id, tutorial_title, tutorial_author FROM clone_table WHERE tutorial_id = 101";
if ($mysqli->query($sql)) {
    printf("View updated successfully!.
");
}
if ($mysqli->errno) {
    printf("View could not be updated!.
", $mysqli->error);
}  
$mysqli->close();

Output

The output obtained is as follows −

View updated successfully!. 

var mysql = require(''mysql2'');
var con = mysql.createConnection({
    host: "localhost",
    user: "root",
    password: "Nr5a0204@123"
});

  //Connecting to MySQL
  con.connect(function (err) {
  if (err) throw err;
  console.log("Connected!");
  console.log("--------------------------");

  sql = "create database TUTORIALS"
  con.query(sql);

  sql = "USE TUTORIALS"
  con.query(sql);

  sql = "CREATE TABLE CUSTOMERS(ID int NOT NULL, NAME varchar(20) NOT NULL, AGE int NOT NULL, ADDRESS varchar(25), SALARY decimal(18, 2), PRIMARY KEY (ID) );"
  con.query(sql);

  sql = "INSERT INTO CUSTOMERS (ID,NAME,AGE,ADDRESS,SALARY) VALUES (1, ''Ramesh'',32, ''Ahmedabad'', 2000.00 ),(2, ''Khilan'',25, ''Delhi'', 1500.00 ),(3, ''kaushik'',23, ''Kota'', 2000.00),(4,''Chaitali'', 25, ''Mumbai'', 6500.00 ),(5, ''Hardik'',27, ''Bhopal'', 8500.00 ),(6, ''Komal'',22, ''MP'', 4500.00 ),(7, ''Muffy'',24, ''Indore'', 10000.00 );"
  con.query(sql);

  sql = "CREATE VIEW CUSTOMERS_VIEW AS SELECT * FROM CUSTOMERS;"
  con.query(sql);

  //Displaying contents of the view
  sql = "SELECT * from CUSTOMERS_VIEW;"
  con.query(sql, function(err, result){
    if (err) throw err
    console.log("**CUSTOMERS_VIEW View:**");
    console.log(result);
    console.log("--------------------------");
  });

  sql = "UPDATE CUSTOMERS_VIEW SET AGE = 35 WHERE name = ''Ramesh''";
  con.query(sql);

  //retrieving the base table
  sql = "SELECT * FROM CUSTOMERS;"
  con.query(sql, function(err, result){
    if (err) throw err
    console.log("**Base Table(CUSTOMERS):**");
    console.log(result);
  });
});

Output

The output produced is as follows −

Connected!
--------------------------
**CUSTOMERS_VIEW View:**
[
  {ID: 1, NAME: ''Ramesh'', AGE: 32, ADDRESS: ''Ahmedabad'', SALARY: ''2000.00''},
  {ID: 2, NAME: ''Khilan'', AGE: 25, ADDRESS: ''Delhi'', SALARY: ''1500.00''},
  {ID: 3, NAME: ''kaushik'', AGE: 23, ADDRESS: ''Kota'', SALARY: ''2000.00''},
  {ID: 4, NAME: ''Chaitali'', AGE: 25, ADDRESS: ''Mumbai'', SALARY: ''6500.00''},
  {ID: 5, NAME: ''Hardik'', AGE: 27, ADDRESS: ''Bhopal'', SALARY: ''8500.00''},
  {ID: 6, NAME: ''Komal'', AGE: 22, ADDRESS: ''MP'', SALARY: ''4500.00'' },
  {ID: 7, NAME: ''Muffy'', AGE: 24, ADDRESS: ''Indore'', SALARY: ''10000.00''}
]
--------------------------
**Base Table(CUSTOMERS):**
[
  {ID: 1, NAME: ''Ramesh'', AGE: 35, ADDRESS: ''Ahmedabad'', SALARY: ''2000.00''},
  {ID: 2, NAME: ''Khilan'', AGE: 25, ADDRESS: ''Delhi'', SALARY: ''1500.00''},
  {ID: 3, NAME: ''kaushik'', AGE: 23, ADDRESS: ''Kota'', SALARY: ''2000.00''},
  {ID: 4, NAME: ''Chaitali'', AGE: 25, ADDRESS: ''Mumbai'', SALARY: ''6500.00''},
  {ID: 5, NAME: ''Hardik'', AGE: 27, ADDRESS: ''Bhopal'', SALARY: ''8500.00''},
  {ID: 6, NAME: ''Komal'', AGE: 22, ADDRESS: ''MP'', SALARY: ''4500.00'' },
  {ID: 7, NAME: ''Muffy'', AGE: 24, ADDRESS: ''Indore'', SALARY: ''10000.00''}
]

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;

public class UpdateView {
   public static void main(String[] args) {
      String url = "jdbc:mysql://localhost:3306/TUTORIALS";
      String username = "root";
      String password = "password";
      try {
         Class.forName("com.mysql.cj.jdbc.Driver");
         Connection connection = DriverManager.getConnection(url, username, password);
         Statement statement = connection.createStatement();
         System.out.println("Connected successfully...!");

         //Update Created View.....
         String sql = "ALTER VIEW first_view AS select tutorial_id, tutorial_title, tutorial_author from tutorials_tbl where tutorial_id = 1";
         statement.execute(sql);
         System.out.println("Created view updated Successfully...!");
         ResultSet resultSet = statement.executeQuery("SELECT * FROM first_view");
         while (resultSet.next()) {
            System.out.print(resultSet.getInt(1)+" "+ resultSet.getString(2)+ " "+ resultSet.getString(3));
            System.out.println();
         }
         connection.close();
      } catch (Exception e) {
         System.out.println(e);
      }
   }
}

Output

The output obtained is as shown below −

Connected successfully...!
Created view updated Successfully...!
1 Learn PHP John Paul

import mysql.connector
#establishing the connection
connection = mysql.connector.connect(
    host=''localhost'',
    user=''root'',
    password=''password'',
    database=''tut''
)
cursorObj = connection.cursor()
update_view_query = """
UPDATE tutorial_view
SET tutorial_title = ''New Title''
WHERE tutorial_id = 2
"""
cursorObj.execute(update_view_query)
connection.commit()
print("View updated successfully.")
cursorObj.close()
connection.close()

Output

Following is the output of the above code −

View updated successfully.

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