public override void Visit(DbElementExpression expression)
{
Write(expression);
_depth++;
Write("Argument", expression.Argument);
_depth--;
}
public override SqlFragment Visit(DbElementExpression expression)
{
SelectStatement s = VisitInputExpressionEnsureSelect(expression.Argument, null, null);
s.Wrap(scope);
return(s);
}
public override void Visit(DbElementExpression e)
{
Check.NotNull(e, "e");
BeginUnary(e);
End(e);
}
/// <summary>
/// Implements the visitor pattern for <see cref="T:System.Data.Common.CommandTrees.DbElementExpression"/>.
/// </summary>
/// <param name="expression">The <see cref="T:System.Data.Common.CommandTrees.DbElementExpression"/> that is visited.</param>
public override void Visit(DbElementExpression expression)
{
if (expression == null)
{
throw new ArgumentNullException("expression");
}
expression.Argument.Accept(this);
}
private DbExpression RewriteElementExpression(DbElementExpression expression)
{
DbExpression rewrittenInput = Rewrite(expression.Argument);
if (!object.ReferenceEquals(expression.Argument, rewrittenInput))
{
expression = rewrittenInput.Element();
}
return(expression);
}
private DbExpression RewriteElementExpression(DbElementExpression expression)
{
DbExpression dbExpression = this.Rewrite(expression.Argument);
if (!object.ReferenceEquals((object)expression.Argument, (object)dbExpression))
{
expression = dbExpression.Element();
}
return((DbExpression)expression);
}
/// <summary>
/// Translate a NewInstance(Element(X)) expression into
/// "select top(1) * from X"
/// </summary>
/// <param name="e"></param>
/// <returns></returns>
private ISqlFragment VisitCollectionConstructor(DbNewInstanceExpression e)
{
Debug.Assert(e.Arguments.Count <= 1);
if (e.Arguments.Count == 1 && e.Arguments[0].ExpressionKind == DbExpressionKind.Element)
{
DbElementExpression elementExpr = e.Arguments[0] as DbElementExpression;
SqlSelectStatement result = VisitExpressionEnsureSqlStatement(elementExpr.Argument);
if (!IsCompatible(result, DbExpressionKind.Element))
{
Symbol fromSymbol;
TypeUsage inputType = MetadataHelpers.GetElementTypeUsage(elementExpr.Argument.ResultType);
result = CreateNewSelectStatement(result, "element", inputType, out fromSymbol);
AddFromSymbol(result, "element", fromSymbol, false);
}
result.Top.SetTopCount(1);
return(result);
}
// Otherwise simply build this out as a union-all ladder
CollectionType collectionType = MetadataHelpers.GetEdmType <CollectionType>(e.ResultType);
Debug.Assert(collectionType != null);
bool isScalarElement = MetadataHelpers.IsPrimitiveType(collectionType.TypeUsage);
SqlBuilder resultSql = new SqlBuilder();
string separator = "";
// handle empty table
if (e.Arguments.Count == 0)
{
Debug.Assert(isScalarElement);
resultSql.Append(" select cast(null as ");
resultSql.Append(MetadataHelpers.GetSqlPrimitiveType(collectionType.TypeUsage));
resultSql.Append(") as x from (select 1) as y where 1=0");
}
foreach (DbExpression arg in e.Arguments)
{
resultSql.Append(separator);
resultSql.Append(" select ");
resultSql.Append(arg.Accept(this));
// For scalar elements, no alias is appended yet. Add this.
if (isScalarElement)
{
resultSql.Append(" as x ");
}
separator = " union all ";
}
return(resultSql);
}
public override Expression Visit(DbElementExpression expression)
{
Expression source = this.Visit(expression.Argument);
Expression single = queryMethodExpressionBuilder.FirstOrDefault(source);
var props = single.Type.GetProperties();
if (props.Length == 1)
{
// If the row record has a single property, it is evaluated too
return(Expression.Property(single, props[0]));
}
return(single);
}
public override Expression Visit(DbElementExpression expression)
{
Expression source = this.Visit(expression.Argument);
Expression single = queryMethodExpressionBuilder.FirstOrDefault(source);
var props = single.Type.GetProperties();
if (props.Length == 1)
{
// If the row record has a single property, it is evaluated too
return Expression.Property(single, props[0]);
}
return single;
}
public override void Visit(DbElementExpression expression)
{
VisitUnaryExpression(expression);
}
public override void Visit(DbElementExpression expression)
{
throw new NotSupportedException("Visit(\"ElementExpression\") is not supported.");
}
private DbExpression RewriteElementExpression(DbElementExpression expression)
{
DbExpression rewrittenInput = Rewrite(expression.Argument);
if (!object.ReferenceEquals(expression.Argument, rewrittenInput))
{
expression = rewrittenInput.Element();
}
return expression;
}
public override void Visit(DbElementExpression expression)
{
throw new NotSupportedException("Visit(\"DbElementExpression\") is not supported.");
}
public override DbExpression Visit(DbElementExpression expression)
{
System.Diagnostics.Debug.Print("Visit(DbElementExpression): {0}", expression);
return base.Visit(expression);
}
public override bool Visit(DbElementExpression expression)
{
Check.NotNull <DbElementExpression>(expression, nameof(expression));
return(this.VisitUnaryExpression((DbUnaryExpression)expression));
}
/// <summary>
/// Visitor pattern method for <see cref="DbElementExpression" />.
/// </summary>
/// <param name="expression"> The DbElementExpression that is being visited. </param>
/// <exception cref="ArgumentNullException">
/// <paramref name="expression" />
/// is null
/// </exception>
public override void Visit(DbElementExpression expression)
{
Check.NotNull(expression, "expression");
VisitUnaryExpression(expression);
}
public override void Visit(DbElementExpression expression)
{
this.VisitUnaryExpression((DbUnaryExpression)expression);
}
public override void Visit(DbElementExpression e)
{
Check.NotNull <DbElementExpression>(e, nameof(e));
this.VisitUnary((DbUnaryExpression)e);
}
public override void Visit(DbElementExpression expression) { }
public override void Visit(DbElementExpression e)
{
VisitUnary(e);
}
public override TreeNode Visit(DbElementExpression e)
{
return(this.VisitUnary(e, true));
}
/// <summary> /// Typed visitor pattern method for DbElementExpression. /// </summary> /// <param name="expression"> The DbElementExpression that is being visited. </param> /// <returns> An instance of TResultType. </returns> public abstract TResultType Visit(DbElementExpression expression);
/// <summary> /// Visitor pattern method for DbElementExpression. /// </summary> /// <param name="expression"> The DbElementExpression that is being visited. </param> public abstract void Visit(DbElementExpression expression);
public override VfpExpression Visit(DbElementExpression expression)
{
return(new VfpElementExpression(expression.ResultType, expression.Argument.Accept(this)));
}
public override DbExpression Visit(DbElementExpression expression)
{
System.Diagnostics.Debug.Print("Visit(DbElementExpression): {0}", expression);
return(base.Visit(expression));
}
public override DbExpressionEntitySetInfo Visit(DbElementExpression expression)
{
Check.NotNull(expression, "expression");
return(null);
}
public override object Visit(DbElementExpression expression)
{
this.Visit(expression.Argument);
return(null);
}
/// <summary> /// Visitor pattern method for DbElementExpression. /// </summary> /// <param name="expression"> The DbElementExpression that is being visited. </param> public abstract void Visit(DbElementExpression expression);
public override LegacyCommandTrees.DbExpression Visit(DbElementExpression expression)
{
Debug.Assert(expression != null, "expression != null");
return(expression.Argument.Accept(this).Element());
}
public override void Visit(DbElementExpression e)
{
BeginUnary(e);
End(e);
}
public override SqlFragment Visit(DbElementExpression expression)
{
throw new NotImplementedException();
}
public override ISqlFragment Visit(DbElementExpression e)
{
// ISSUE: What happens if the DbElementExpression is used as an input expression?
// i.e. adding the '(' might not be right in all cases.
return(new SqlBuilder("(", VisitExpressionEnsureSqlStatement(e.Argument), ")"));
}
public override TreeNode Visit(DbElementExpression e)
{
Check.NotNull <DbElementExpression>(e, nameof(e));
return(this.VisitUnary((DbUnaryExpression)e, true));
}
public override void Visit(DbElementExpression expression)
{
VisitUnaryExpression(expression);
}
public override void Visit(DbElementExpression e)
{
VisitUnary(e);
}
public override bool Visit(DbElementExpression expression)
{
return(VisitUnaryExpression(expression));
}
public override void Visit(DbElementExpression e)
{
Check.NotNull(e, "e");
VisitUnary(e);
}
public override TReturn Visit(DbElementExpression expression)
{
Check.NotNull <DbElementExpression>(expression, nameof(expression));
throw this.ConstructNotSupportedException((DbExpression)expression);
}
public override SqlFragment Visit(DbElementExpression expression)
{
SelectStatement s = VisitInputExpressionEnsureSelect(expression.Argument, null, null);
s.Wrap(scope);
return s;
}
public override TReturn Visit(DbElementExpression expression)
{
throw ConstructNotSupportedException(expression);
}
public override TreeNode Visit(DbElementExpression e)
{
Check.NotNull(e, "e");
return(VisitUnary(e, true));
}
public override void Visit(DbElementExpression expression)
{
Contract.Requires(expression != null);
}
public override DbExpressionEntitySetInfo Visit(DbElementExpression expression)
{
return(null);
}
/// <summary>
/// Implements the visitor pattern for <see cref="T:System.Data.Common.CommandTrees.DbElementExpression"/>.
/// </summary>
/// <param name="expression">The <see cref="T:System.Data.Common.CommandTrees.DbElementExpression"/> that is visited.</param>
public override void Visit(DbElementExpression expression)
{
if (expression == null)
{
throw new ArgumentNullException("expression");
}
expression.Argument.Accept(this);
}
