Tài liệu Finding Rows in a DataTable ppt

... shown in the sample code to locate data in the table meeting user-specified criteria. The sample code contains two event handlers: Form.Load Sets up the sample by creating a DataTable containing ... [ Team LiB ] Recipe 3.8 Finding Rows in a DataTable Problem You need to find a row or group of rows in a DataTable meeting certain criteria. Solution Choose...

Ngày tải lên: 26/01/2014, 10:20

... the DataAdapter object. Adding a DataRow to a DataTable In this section, you'll learn how to add a DataRow to a DataTable. Before you see this, let's populate a DataSet with the rows ... DeleteCommand properties of a DataAdapter. Setting the InsertCommand Property of a DataAdapter The following example creates a SqlCommand object named myInsertCommand tha...

Ngày tải lên: 24/12/2013, 01:17

... Team LiB ] Recipe 3.9 Finding Rows in a DataView Problem You need to find a row or group of rows in a DataView meeting certain criteria. Solution Use a sorted DataView to find rows using ... no match is found) while FindRows( ) returns a DataRowView array of all matching rows (or an empty array if no match is found). The DataRow for a DataRowView can be ac...

Ngày tải lên: 14/12/2013, 18:16

... overloaded as follows: int Update(DataRow[] myDataRows) int Update(DataSet myDataSet) int Update (DataTable myDataTable) int Update(DataRow[] myDataRows, DataTableMapping myDataTableMapping) int ... DisplayDataRow() is as follows: In AddDataRow() Calling myDataTable.NewRow() myNewDataRow.RowState = Detached Calling myDataTable .Rows. Add() myNewDataRow.RowState = Added Calling m...

Ngày tải lên: 24/12/2013, 01:17

... objects in a DataTable. Finding a DataRow in a DataTable To find a DataRow in a DataTable, you follow these steps: 1. Retrieve the rows from the database into your DataTable. 2. Set the PrimaryKey ... Finding, Filtering, and Sorting Rows in a DataTable Each row in a DataTable is stored in a DataRow object, and in this section you'll learn...

Ngày tải lên: 14/12/2013, 13:15

... retrieved by default when accessing rows in a DataTable or in a DataView. The solution demonstrates an approach for getting Deleted rows from both a DataTable and a DataView. Deleted rows include only ... dv.RowStateFilter = DataViewRowState.Deleted; dataGrid.ReadOnly = true; // Get the DataTable from the DataView. DataTable dt = dv.Table; // Filter using t...

Ngày tải lên: 14/12/2013, 18:16

... forward-only, read-only access to a stream of rows from a data source. It is optimized for performance by reading data directly from a connection to a data source. As a result, there is no way ... Iterate over the rows in the DataReader. • Issue a COUNT(*) query as part of a batch query. Note that not all data sources support batch queries. If not, execute the statem...

Ngày tải lên: 24/12/2013, 05:15

... [ Team LiB ] Recipe 3.10 Selecting the Top n Rows in a DataTable Problem You want to create a grid that shows the t op five rows in a DataTable, based on the values in one of the ... Solution Use an appropriate sort order with a DataView filter. The sample code contains two event handlers: Form.Load Sets up the sample by creating a DataTable containing the...

Ngày tải lên: 14/12/2013, 18:16

... the database. Using a DataGrid Control to Access a Database A DataGrid allows you to access rows in a database table. In the following sections, you'll learn how to create an ASP.NET ... create a DataSet object. You use a DataSet object to store a local copy of the information stored in the database. A DataSet object can represent database structures su...

Ngày tải lên: 24/12/2013, 01:17

... include inner joins, left outer joins, and right outer joins. Inner Join This join displays records in which at least one record exists in each table for the joined field. This means that ... ' Store the SQL String Me.lblSQLString.Text = strSQL ' Use the SQL String to build the data adapter and fill the data table. Dim odaResults As New OleDb.OleDbDataAdapter(Me....

Ngày tải lên: 21/01/2014, 12:20