DataContext.ExecuteQuery<TResult> Method (String, Object[])
Executes SQL queries directly on the database and returns objects.
Assembly: System.Data.Linq (in System.Data.Linq.dll)
public IEnumerable<TResult> ExecuteQuery<TResult>( string query, params object[] parameters )
Parameters
- query
-
Type:
System.String
The SQL query to be executed.
- parameters
-
Type:
System.Object[]
The array of parameters to be passed to the command. Note the following behavior:
If the number of objects in the array is less than the highest number identified in the command string, an exception is thrown.
If the array contains objects that are not referenced in the command string, no exception is thrown.
If a parameter is null, it is converted to DBNull.Value.
Return Value
Type: System.Collections.Generic.IEnumerable<TResult>A collection of objects returned by the query.
Type Parameters
- TResult
The type of the elements in the returned collection.
This method is a pass-through mechanism for cases where LINQ to SQL does not provide for a particular scenario.
The algorithm for matching columns in the result of the query to fields and properties in the object works as follows:
If a field or property is mapped to a particular column name, that column name is expected in the resultset.
If a field or property is not mapped, a column with the same name as the field or property is expected in the resultset.
The comparison is performed by first looking for a case-sensitive match. If such a match is not found, a subsequent search occurs for a case-insensitive match.
The query must return all the tracked fields and properties of the object (apart from those subject to deferred loading) when all the following are true:
If <T> is an entity explicitly tracked by the DataContext.
ObjectTrackingEnabled is true.
The entity has a primary key.
Otherwise an exception is thrown.
In all other cases, the query can retrieve just a subset of the tracked fields and properties for the object.
The following C# snippet shows one use for this method:
var customers = db.ExecuteQuery<Customer>(@"SELECT CustomerID, CompanyName, ContactName, ContactTitle,
Address, City, Region, PostalCode, Country, Phone, Fax
FROM dbo.Customers
WHERE City = {0}", "London");
foreach (Customer c in customers)
Console.WriteLine(c.ContactName);
In Visual Basic
Dim customers = db.ExecuteQuery(Of Customer)("SELECT CustomerID, _ CompanyName, ContactName, ContactTitle, _
Address, City, Region, PostalCode, Country, Phone, Fax _
FROM dbo.Customers _
WHERE City = {0}", "London")
For Each c As Customer In customers
Console.WriteLine(c.ContactName)
Next
Available since 3.5