Data Updating and Deleting with Visual C# · 3. Submit changes to the DataContext The data will...
Transcript of Data Updating and Deleting with Visual C# · 3. Submit changes to the DataContext The data will...
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DATA UPDATING AND DELETING WITH
VISUAL C#.NET
Ayşe Şadiye Özen
2013514054
GENERAL INFORMATION
In 7th chapter from Ying Bai Practical Database
book, we will learn about update and delete
data in the database.
There are 2 method for this application.
1. Table Adapter Manager
2. With runtime objects(ExecuteNonQuery())
TABLE ADAPTER MANAGER
TableAdapter is utilized to perform a data query and all data tables are embedded into the DataSet as a data - catching unit, the Command object is embedded into the different data query methods of the TableAdapter, such as
SelectCommand,
InsertCommand,
UpdateCommand,
DeleteCommand, and is executed based on the associated query type.
TABLEADAPTER.INSERT
Adds new records into a database allowing you
to pass in individual column values as method
parameters.
TABLEADAPTER.UPDATE
Updates existing records in a database. The Update method takes original and new column values as method parameters. The original values are used to locate the original record, and the new values are used to update that record. The TableAdapter.Update method is also used to reconcile changes in a data set back to the database by taking a DataSet, DataTable, DataRow, or array of DataRows asmethod parameters.
TABLEADAPTER.DELETE
Deletes existing records from the database
based on the original column values passed in
as method parameters.
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Let’s take an example about Table Adapter.
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4 Textbox
4 Button
WITH RUN TIME OBJECTS
In this part, we will use SQL and LINQ and
discuss how to update and delete data in the
databases.
SQL
We known, SQL is a standardized programming
language used for managing relational
databases and performing various operations
on the data in them.
We can update and delete operations with
ExecuteNonQuery() method.
EXECUTENONQUERY()
The ExecuteNonQuery() is one of the most frequently used method in SqlCommand Object and is used for executing statements that do not return result sets (ie. statements like insert data, update data etc.) .
Command.ExecuteNonQuery(): The ExecuteNonQuery() performs Data Definition tasks as well as Data Manipulation tasks also. The Data Definition tasks like creating Stored Procedures,Views etc. perform by the
ExecuteNonQuery() . Also Data Manipulation tasks like Insert, Update, Delete etc. also perform by the ExecuteNonQuery() of SqlCommand Object.
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Firstly, we will create a database at SQL Server.
4 Button
1 DataGridView
6 Label
6 Textbox
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LINQ
We known, LINQ is a Microsoft programming
model and methodology that essentially adds
formal query capabilities into Microsoft.
We can apply update and delete operations.
UPDATING EXISTING DATA
1. Retrieve the object to be changed from the DataContext
Use LINQ to retrieve the category you want to update from your DataContext.
LINQ's Single method provides an easy way to do this by taking a lambda expression that returns a single object. In this case, the category (c) whose Name == "Programming Practices":
BookCatalog bookCatalog = new BookCatalog( ); Category category = bookCatalog.Categories.Single( c => c.Name == "Programming Practices" );
2. Update the object
category.Name = "Technical Practices";
3. Submit changes to the DataContext
bookCatalog.SubmitChanges( );
DELETING DATA
Similarly, you can remove records from the database by removing them from the appropriate Table collection in your DataContext.
1. Retrieve object to be changed from the DataContext
Retrieve the object you want to delete from your DataContext:
BookCatalog bookCatalog = new BookCatalog( ); Category category = bookCatalog.Categories.Single( c => c.Name == "Java" );
2. Remove the object from the appropriate Table collection in your DataContext
This is done with the DeleteOnSubmit() method on your Table collection:
bookCatalog.Categories.DeleteOnSubmit( category );
3. Submit changes to the DataContext
The data will have been removed locally from your DataContext, but will not be deleted from the database until you call SubmitChanges().
bookCatalog.SubmitChanges( );
Firstly, we will create a new sql database.
6 Label
4 Button
6 Textbox
1 DataGridView
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And then, we should add LINQ class our
project.
We should catch and drag our table. Then, we should see this.
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REFERENCES
https://searchsqlserver.techtarget.com/definition/SQL
https://www.codeproject.com/Articles/46422/A-LINQ-Tutorial-Adding-Updating-Deleting-Data
https://www.youtube.com/watch?v=fur4nsLa5VU
https://www.ahmetcansever.com/sql-server-2/c-telefon-rehberi-linq-to-sql-classes-select-insert-update-delete/
https://docs.microsoft.com/tr-tr/visualstudio/data-tools/fill-datasets-by-using-tableadapters
Practical Database Programming With Visual C#.NET, by Ying Bai