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This article introduces the knowledge about "ADO. NET DataTable object how to create". In the actual case operation process, many people will encounter such difficulties. Next, let Xiaobian lead you to learn how to deal with these situations! I hope you can read carefully and learn something!

ADO. NET can process data through DataSet or DataTable objects while disconnecting from the database, reconnecting to the data source when data needs to be updated, and updating the data source. DataTable objects represent tables stored in native memory and provide various operations on row and column data objects in the tables. DataTable objects can be populated directly with data from a database, or DataTable objects can be added to existing DataSet objects. In the disconnected mode, DataSet object provides the same relational data model as relational database. DataTable object in DataSet object can be accessed directly in code, and DataTable object can also be added and deleted.

1. Creating ADO. NET DataTable Objects

DataTable objects can be created in two ways:

1)DataTable objects are created through constructors of DataTable classes, for example:

DataTable table = new DataTable();

2)Create DataTable objects through the Add method of the Tables object of the DataSet, for example:

DataSet dataset = new DataSet(); DataTable table = dataset.Tables.Add("MyTableName");

2. Add columns to DataTable objects

The most common way to add columns to a DataTable object is through the Add method in the Column property of the DataTable object. Each column added is a DataColumn object.

3. Set primary key of DataTable object

Tables in relational databases typically have a primary key that uniquely identifies each row in the table. The DataTable object's PrimaryKey property allows you to set the Datatable's primary key. A primary key can be an array of one or more DataColumn objects. For example:

DataColumn[] key = new DataColumn[1];//dt is a DataTable object key[0] = dt.Columns[0]; dt.PrimaryKey = key;

4. Create rows in DataTable objects

Each row of DataTable object is a DataRow object, so when creating rows, you can first create a DataRow object by using the NewRow method of DataTable object, and set the data of each column in the new row, and then add DataRow object to the table by using the Add method.

5. Populate DataTable with tables from SQL Server database

In addition to creating rows and columns of DataTable objects directly, you can also fill DataTable objects with tables from SQL Server databases through the Fill method of DateAdapter objects.

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