public QueryModel Apply (QueryModel queryModel, ClauseGenerationContext clauseGenerationContext)
{
if (queryModel != null)
throw new ArgumentException ("QueryModel has to be null because MainSourceExpressionNode marks the start of a query.", "queryModel");
var mainFromClause = CreateMainFromClause (clauseGenerationContext);
var defaultSelectClause = new SelectClause (new QuerySourceReferenceExpression (mainFromClause));
return new QueryModel (mainFromClause, defaultSelectClause) { ResultTypeOverride = QuerySourceType };
}
/// <summary>
/// Modifies the given query model for fetching, adding an <see cref="AdditionalFromClause"/> and changing the <see cref="SelectClause.Selector"/> to
/// retrieve the result of the <see cref="AdditionalFromClause"/>.
/// For example, a fetch request such as <c>FetchMany (x => x.Orders)</c> will be transformed into a <see cref="AdditionalFromClause"/> selecting
/// <c>y.Orders</c> (where <c>y</c> is what the query model originally selected) and a <see cref="SelectClause"/> selecting the result of the
/// <see cref="AdditionalFromClause"/>.
/// This method is called by <see cref="FetchRequestBase.CreateFetchQueryModel"/> in the process of creating the new fetch query model.
/// </summary>
protected override void ModifyFetchQueryModel (QueryModel fetchQueryModel)
{
ArgumentUtility.CheckNotNull ("fetchQueryModel", fetchQueryModel);
var fromExpression = GetFetchedMemberExpression (new QuerySourceReferenceExpression (fetchQueryModel.MainFromClause));
var memberFromClause = new AdditionalFromClause (fetchQueryModel.GetNewName ("#fetch"), _relatedObjectType, fromExpression);
fetchQueryModel.BodyClauses.Add (memberFromClause);
var newSelector = new QuerySourceReferenceExpression (memberFromClause);
var newSelectClause = new SelectClause (newSelector);
fetchQueryModel.SelectClause = newSelectClause;
}
/// <summary>
/// Initializes a new instance of <see cref="QueryModel"/>
/// </summary>
/// <param name="mainFromClause">The <see cref="Clauses.MainFromClause"/> of the query. This is the starting point of the query, generating items
/// that are filtered and projected by the query.</param>
/// <param name="selectClause">The <see cref="SelectClause"/> of the query. This is the end point of
/// the query, it defines what is actually returned for each of the items coming from the <see cref="MainFromClause"/> and passing the
/// <see cref="BodyClauses"/>. After it, only the <see cref="ResultOperators"/> modify the result of the query.</param>
public QueryModel (MainFromClause mainFromClause, SelectClause selectClause)
{
ArgumentUtility.CheckNotNull ("mainFromClause", mainFromClause);
ArgumentUtility.CheckNotNull ("selectClause", selectClause);
_uniqueIdentifierGenerator = new UniqueIdentifierGenerator();
MainFromClause = mainFromClause;
SelectClause = selectClause;
BodyClauses = new ObservableCollection<IBodyClause>();
BodyClauses.CollectionChanged += BodyClauses_CollectionChanged;
ResultOperators = new ObservableCollection<ResultOperatorBase>();
ResultOperators.CollectionChanged += ResultOperators_CollectionChanged;
}
public virtual void VisitSelectClause (SelectClause selectClause, QueryModel queryModel)
{
ArgumentUtility.CheckNotNull ("selectClause", selectClause);
ArgumentUtility.CheckNotNull ("queryModel", queryModel);
// nothing to do here
}
public override void VisitSelectClause(SelectClause selectClause, QueryModel queryModel)
{
QueryText.Append(" return ");
GetAqlExpression(selectClause.Selector, queryModel);
}
/// <summary>
/// Clones this clause.
/// </summary>
/// <param name="cloneContext">The clones of all query source clauses are registered with this <see cref="CloneContext"/>.</param>
/// <returns>A clone of this clause.</returns>
public SelectClause Clone (CloneContext cloneContext)
{
ArgumentUtility.CheckNotNull ("cloneContext", cloneContext);
var result = new SelectClause (Selector);
return result;
}
/// <summary>
/// Creates a new <see cref="QueryModel"/> that has this <see cref="QueryModel"/> as a sub-query in its <see cref="MainFromClause"/>.
/// </summary>
/// <param name="itemName">The name of the new <see cref="QueryModel"/>'s <see cref="FromClauseBase.ItemName"/>.</param>
/// <returns>A new <see cref="QueryModel"/> whose <see cref="MainFromClause"/>'s <see cref="FromClauseBase.FromExpression"/> is a
/// <see cref="SubQueryExpression"/> that holds this <see cref="QueryModel"/> instance.</returns>
public QueryModel ConvertToSubQuery (string itemName)
{
ArgumentUtility.CheckNotNullOrEmpty ("itemName", itemName);
var outputDataInfo = GetOutputDataInfo() as StreamedSequenceInfo;
if (outputDataInfo == null)
{
var message = string.Format (
"The query must return a sequence of items, but it selects a single object of type '{0}'.",
GetOutputDataInfo ().DataType);
throw new InvalidOperationException (message);
}
// from x in (sourceItemQuery)
// select x
var mainFromClause = new MainFromClause (
itemName,
outputDataInfo.ResultItemType,
new SubQueryExpression (this));
var selectClause = new SelectClause (new QuerySourceReferenceExpression (mainFromClause));
return new QueryModel (mainFromClause, selectClause);
}
