Updating data sources with dataadapters
This walkthrough supposes that you know how to connect to server, how to create the necessary objects on the server, and how to insert the data to the created tables. NET serve as a bridge between an application and a data source, and allow you to execute commands as well as to retrieve data by using a Data Reader or a Data Adapter. Print Dept(conn) ' updating records in Dept Module1.Note that if you do not use design-time (specifically, if you do not place on a designer My Sql Connection component from toolbox), you have to embed license information manually. As we know, an original function of any database application is establishing a connection to a data source and working with data contained in it. Updating data involves using the Command and Data Adapter objects; and it may also involve using transactions. New Line) ' Always call Read before accesing data While reader. Modify Dept(conn) ' printing out the Dept table to console Module1. Read Line() End Try End Using End Sub End Module A traditional way for working with Data Table and Data Set assumes consecutive creating and initializing Connection, Command, Data Adapter, and Command Builder objects.NET, don't interoperate with datasource immediately. These classes provide the ability to work off-line against your data storage: Data Set, Data Table, Data Column, Data Row, Constraints, Data Relation, Data View, and Data Row View. Public Sub Use Data Table() Dim my Data Table As My Sql Data Table _ As New My Sql Data Table("SELECT * FROM Dept", "User Id=root; Host=localhost; Database=Test;") Try ' Fetch All=true means to retrieve data from server entirely when Data Table is opened.We will use in our samples the classes from both models. ' By default, Fetch All is set to false - only minimal quantity of rows is requested at once, ' which leads to better initial response time and less network traffic. Fetch All = True ' populating Data Table with data from data source my Data Table. Write(my Row(my Col) & Vb Crlf) Next my Col Console. New Line) End While End Using End Sub Sub Modify Dept(By Val connection As My Sql Connection) Dim command As My Sql Command = connection. Command Text = "UPDATE DEPT SET LOC='VEGAS' WHERE DEPTNO 20" ' return value of Execute Non Query (i) is the number of rows affected by the command Dim i As Integer = command. New Line) End Sub Sub Main() Using conn _ As New My Sql Connection("User Id=root; Host=localhost; Database=Test;") Try conn. New Line & "Rows in DEPT updated: ", i & Environment.This tutorial describes only basic ways of working with data.
My Sql Data Adapter and My Sql Data Table components are available for full . Thus, you cannot use disconnected model classes and My Sql Data Adapter in projects targeted . Rows(3)("DName") = "Researches" ' Update method executes the appropriate commands (delete, insert, or update) in the data source. Please refer to our Using Data Set Wizard and Using Data Set Manager articles.
dot Connect for My SQL supports the Linq Connect and Entity Framework ORM technologies which are intended for converting data between incompatible type systems in relational databases and object-oriented programming languages.
These technologies allow you to decrease the amount of code and maintenance required for data-oriented applications.
When querying data, there are two mechanisms we can use: a Data Reader or a Data Adapter.
Even though we are comparing Data Reader & Data Adapter, underneath the abstractions, a Data Adapter uses a Data Reader to populate the returned Data Set or Data Table.