OleDbDataAdapter.Fill Method (DataTable, Object)
Assembly: System.Data (in System.Data.dll)
- Type: System.Data.DataTable
A DataTable to fill with records and, if it is required, schema.
- Type: System.Object
An ADO Recordset or Record object.
The link between ActiveX Data Objects (ADO) and ADO.NET is a one-way operation in that you can copy data from ADO to the DataSet, but any updates to the data must be handled by ADO.NET.
When handling batch SQL statements that return multiple results, this implementation of Fill and FillSchema for the OLE DB.NET Framework Data Provider retrieves schema information for only the first result.
The Fill operation adds the rows to the specified destination DataTable object in the DataSet, creating the DataTable object if it does not already exist. When you create a DataTable object, the Fill operation ordinarily creates only column name metadata. However, if the MissingSchemaAction property is set to AddWithKey, appropriate primary keys and constraints are also created.
You can use the Fill method multiple times on the same DataTable. If a primary key exists, incoming rows are merged with matching rows that already exist. If no primary key exists, incoming rows are appended to the DataTable. If primary key information is present, any duplicate rows are reconciled and only appear one time in the DataTable that corresponds to the DataSet. Primary key information may be set either through FillSchema, by specifying the PrimaryKey property of the DataTable, or by setting the MissingSchemaAction property to AddWithKey.
If the SelectCommand returns the results of an OUTER JOIN, the DataAdapter does not set a PrimaryKey value for the resulting DataTable. You must explicitly define the primary key to make sure that duplicate rows are resolved correctly. For more information, see Defining Primary Keys.
To function correctly with the .NET Framework Data Provider for OLE DB, AddWithKey requires that the native OLE DB provider obtains required primary key information by setting the DBPROP_UNIQUEROWS property, and then determines which columns are primary key columns by examining DBCOLUMN_KEYCOLUMN in the IColumnsRowset. Alternatively the user may explicitly set the primary key constraints on each DataTable. This makes sure that incoming records that match existing records are updated instead of appended.
If the OleDbDataAdapter encounters duplicate columns while populating a DataTable, it generates names for the subsequent columns, using the pattern "columnname1", "columnname2", "columnname3", and so on. Empty column names are added to the DataTable, using an empty string for the first column, followed by "1", "2", "3", and so on for the subsequent empty columns.
Values in ADO Recordset or Record objects are converted to common language runtime types for storage in the DataSet.
This overload of the Fill method does not implicitly call Close on the ADO object when the fill operation is complete. Therefore, always call Close when you are finished using ADO Recordset or Record objects. This makes sure that the underlying connection to a data source is released in a timely manner, and also prevents possible access violations because of unmanaged ADO objects being reclaimed by garbage collection when existing references still exist.
When you call the TableMappings.Add method on a DataAdapter and you explicitly map the source table parameter to an empty string, the dataset is successfully filled using the source table, but the dataset will be populated with nothing. For example, in the following example, rDataSet will be populated with nothing.
rAdapter.TableMappings.Add("source table", ""); rAdapter.Fill(rDataSet, "source table");
This example shows how you can skip a result when dealing with multiple results.
OleDbDataAdapter custDA = new OleDbDataAdapter(); DataSet custDS = new DataSet(); DataTable custTable = new DataTable("Customers"); custTable.Columns.Add("CustomerID", typeof(String)); custTable.Columns.Add("CompanyName", typeof(String)); custDS.Tables.Add(custTable); //Use ADO objects from ADO library (msado15.dll) imported // as.NET library ADODB.dll using TlbImp.exe ADODB.Connection adoConn = new ADODB.Connection(); ADODB.Recordset adoRS = new ADODB.Recordset(); adoConn.Open("Provider=SQLOLEDB;Data Source=localhost;Initial Catalog=Northwind;Integrated Security=SSPI;", "", "", -1); adoRS.Open("SELECT CustomerID, CompanyName FROM Customers", adoConn, ADODB.CursorTypeEnum.adOpenForwardOnly, ADODB.LockTypeEnum.adLockReadOnly, 1); custDA.Fill(custTable, adoRS); adoRS.Close(); adoConn.Close();
Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.