public static Expression PrepareExpressionFromAnonymous <TSource>(Expression sourceExpression, Expression <Func <TSource, object> > expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
// Anonymous initializations are not implemented as member initialization but as plain constructor call.
var newExpression = expression.Body as NewExpression ??
throw new ArgumentException("The expression must be an anonymous initialization, e.g. x => new { Name = x.Name, Age = x.Age + 5 }");
var instance = new DmlExpressionRewriter(expression.Parameters);
instance.AddSettersFromAnonymousConstructor(newExpression, "");
return(PrepareExpression <TSource>(sourceExpression, instance._assignments));
}
public static Expression PrepareExpression <TSource, TTarget>(Expression sourceExpression, Expression <Func <TSource, TTarget> > expression)
{
if (expression == null)
{
throw new ArgumentNullException(nameof(expression));
}
var memberInitExpression = expression.Body as MemberInitExpression ??
throw new ArgumentException("The expression must be a member initialization, e.g. x => new Dog { Name = x.Name, Age = x.Age + 5 }, " +
// If someone call InsertSyntax<TSource>.As(source => new {...}), the code will fail here, so we have to hint at how to correctly
// use anonymous initialization too.
"or an anonymous initialization with an explicitly specified target type when inserting");
if (memberInitExpression.Type != typeof(TTarget))
{
throw new TypeMismatchException($"Expecting an expression of exact type {typeof(TTarget).AssemblyQualifiedName} " +
$"but got {memberInitExpression.Type.AssemblyQualifiedName}");
}
var instance = new DmlExpressionRewriter(expression.Parameters);
instance.AddSettersFromBindings(memberInitExpression.Bindings, "");
return(PrepareExpression <TSource>(sourceExpression, instance._assignments));
}
/// <summary>
/// Perform an <c>update versioned</c> on the entities. The update operation is performed in the database without reading the entities out of it.
/// </summary>
/// <returns>The number of updated entities.</returns>
public int UpdateVersioned()
{
return(_source.ExecuteUpdate(DmlExpressionRewriter.PrepareExpression <TSource>(_source.Expression, _assignments.List), true));
}
/// <summary>
/// Perform an <c>update versioned</c> on all entities selected by the specified query, using an anonymous initializer for specifying setters.
/// The update operation is performed in the database without reading the entities out of it.
/// </summary>
/// <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
/// <param name="source">The query matching the entities to update.</param>
/// <param name="expression">The assignments expressed as an anonymous object, e.g.
/// <c>x => new { Name = x.Name, Age = x.Age + 5 }</c>. Unset members are ignored and left untouched.</param>
/// <returns>The number of updated entities.</returns>
public static int UpdateVersioned <TSource>(this IQueryable <TSource> source, Expression <Func <TSource, object> > expression)
{
return(ExecuteUpdate(source, DmlExpressionRewriter.PrepareExpressionFromAnonymous(source.Expression, expression), true));
}
/// <summary>
/// Update all entities selected by the specified query. The update operation is performed in the database without reading the entities out of it.
/// </summary>
/// <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
/// <param name="source">The query matching the entities to update.</param>
/// <param name="expression">The update setters expressed as a member initialization of updated entities, e.g.
/// <c>x => new Dog { Name = x.Name, Age = x.Age + 5 }</c>. Unset members are ignored and left untouched.</param>
/// <returns>The number of updated entities.</returns>
public static int Update <TSource>(this IQueryable <TSource> source, Expression <Func <TSource, TSource> > expression)
{
return(ExecuteUpdate(source, DmlExpressionRewriter.PrepareExpression(source.Expression, expression), false));
}
/// <summary>
/// Insert all entities selected by the specified query, using an anonymous initializer for specifying setters. <typeparamref name="TTarget"/>
/// must be explicitly provided, e.g. <c>source.InsertInto<Cat, Dog>(c => new {...})</c>. The insert operation is performed in the
/// database without reading the entities out of it.
/// </summary>
/// <typeparam name="TSource">The type of the elements of <paramref name="source" />.</typeparam>
/// <typeparam name="TTarget">The type of the entities to insert. Must be explicitly provided.</typeparam>
/// <param name="source">The query matching entities source of the data to insert.</param>
/// <param name="expression">The expression projecting a source entity to an anonymous object representing
/// the entity to insert.</param>
/// <returns>The number of inserted entities.</returns>
public static int InsertInto <TSource, TTarget>(this IQueryable <TSource> source, Expression <Func <TSource, object> > expression)
{
return(ExecuteInsert <TSource, TTarget>(source, DmlExpressionRewriter.PrepareExpressionFromAnonymous(source.Expression, expression)));
}