How to Use MySqlCommand Component

This tutorial describes how to use MySqlCommand component to insert data into tables by means of executing SQL queries.

This walkthrough supposes that you know how to connect to server (tutorial Logging onto the server) and that necessary objects are already created on the server (tutorial Creating database objects).

 

Note that if you do not use design-time (specifically, if you do not place on a designer MySqlConnection component from toolbox), you have to embed licensing information manually. This is described in dotConnect for MySQL documentation.

General information

Data on server can be modified (inserted, changed or deleted) using Data Manipulation Language (DML), which is a part of SQL. The DML statements can be executed on server by account that has necessary privileges.

There are two ways to manipulate a database. You can build DML statements manually and run them within some component like MySqlCommand. Another way is to use design-time features that provide graphical user interface to manage database. We will discuss both ways.

The goal of this tutorial is to insert the following data into tables dept and emp :

Table dept

deptno	dname	loc
10	Accounting	New York
20	Sales	Dallas
30	Sales2	Chicago

Table emp

empno	ename	job	mgr	hiredate	sal	comm	deptno
7369	Smith	Clerk	7566	1980-12-17	800	Null	20
7499	Allen	Salesman	7698	1981-02-20	1600	300	30
7521	Ward	Salesman	7698	1981-02-22	1250	500	30
7566	Jones	Manager	7839	1981-04-02	2975	Null	20
7654	Martin	Salesman	7698	1981-09-28	1250	1400	30
7698	Blake	Manager	7839	1981-05-01	2850	Null	30
7839	King	President	Null	1981-11-17	5000	Null	10

Inserting data in run time

To insert the first row into table dept you can use the following statement:

INSERT INTO demo.dept (deptno, dname, loc) VALUES (10,'Accounting','New York')

The following code fragment executes the query:

[C#]

MySqlConnection conn = new MySqlConnection("User Id=root;Password=mypassword;Host=127.0.0.1;");
MySqlCommand cmd = new MySqlCommand();
cmd.CommandText = "INSERT INTO dept (deptno, dname, loc) VALUES (10,'Accounting','New York')";
cmd.Connection = conn;
conn.Open();
try {
  int aff = cmd.ExecuteNonQuery();
  MessageBox.Show(aff + " rows were affected.");
}
catch {
  MessageBox.Show("Error encountered during INSERT operation.");
}
finally {
  conn.Close();
}

[Visual Basic]

Dim conn As MySqlConnection = New MySqlConnection("User Id=root;Password=mypassword;Host=127.0.0.1;")
Dim cmd As MySqlCommand = New MySqlCommand()
cmd.CommandText = "INSERT INTO dept (deptno, dname, loc) VALUES (10,'Accounting','New York')"
cmd.Connection = conn
conn.Open()
Try
  Dim aff As Integer = cmd.ExecuteNonQuery()
  MessageBox.Show(aff & " rows were affected.")
Catch
  MessageBox.Show("Error encountered during INSERT operation.")
Finally
  conn.Close()
End Try

The sample first creates a connection with hardcoded connection string. Then it creates MySqlCommand object, assigns the query text and connection to the MySqlCommand instance. Connection is opened then. The ExecuteNonQuery() method of MySqlCommand runs SQL statement in the CommandText property and returns number of rows affected by the query. This method is not intended to run SELECT statements. We will discuss retrieving data in other tutorials.

If the query is executed successfully you are notified about number of affected rows. If some error occurs you get the error message. The connection is closed anyway. It is recommended that you use try ... finally clauses to make sure the connections are closed properly.

Note that the database is explicitly mentioned in the query. This is because we did not specify default database in the connection string. To avoid this we could add the following argument to the connection string: database=demo;.

Design time setup

The same operations in design time include following steps:

1. Place MySqlConnection component on a designer.
2. Setup its properties and open connection by changing the State property to Open
   - or -
   right-click on the component, choose Connect item and use the dialog to connect to server.
3. Place MySqlCommand component on the designer.
4. In its Connection property select name of the MySqlConnection instance on the designer.
5. In the CommandText property type in the following query:
   INSERT INTO dept VALUES (20,'Sales','Dallas')
   
6. Right-click on the MySqlCommand and choose Execute from shortcut menu.
7. Repeat steps 5 and 6 with the following CommandText:
   INSERT INTO dept VALUES (30,'Sales2','Chicago')

Note that the last two steps might be easier to do in the MySqlCommand editor. To invoke it choose CommandText item form MySqlCommand shortcut menu or click on the ellipsis in this property in Properties window.

Using dbForge Fusion for MySQL

Sometimes it is very handy to modify data in design time. This section describes one of the ways to edit data in a grid. These operations are convenient to do in dbForge Fusion for MySQL.

1. In Database Explorer connect to server and browse to the table Emp (for detailed information on how to do it refer to the tutorial Creating Database Objects).
2. Right-click on it and choose Retrieve Data from shortcut menu.
   The editor appears where you can see what data the table contains if any.
3. Click the Append button (+) or press <insert> key.
4. Click on the very first cell. Type in value: 7369.
5. Click on the next cell or hit <Tab>, type in: Smith.
6. In the following cell, type: Clerk.
7. Go on filling the row until you reach the last column. Press <Enter> key to apply inserting the row.
8. Click on the first cell of the second row. Now you have to fill it starting with value 7499. Repeat steps 3-7 to insert all required rows into the table.

Conclusion

This tutorial describes how you can use MySqlCommand component to insert data into tables. Actually there are lots of ways to insert data into tables. Any tool or component that is capable of running a SQL query, can be used to manage data. Some components are best for performing certain tasks. For example, MySqlLoader is the fastest way to insert data, MySqlScript is designed for executing series of statements. For more information on these components refer to dotConnect for MySQL documentation.

More dotConnect for MySQL tutorials

• Creating Database Objects
• How to connect MySQL or MariaDB databases in .NET applications
• Entity Framework Tutorial
• Entity Framework Core Database-First Tutorial for Full .NET Framework
• Tutorial: How to Connect Visual Studio LightSwitch to MySQL
• LINQ to MySQL Tutorial
• SimpleMembership and SimpleRole Providers for MySQL in ASP.NET MVC 4 Application Tutorial

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