public override Identifier Visit(EntityIdentifier identifier)
{
if (visitingColumns)
{
currentAlias = identifier.Entity.Alias;
return identifier;
}
return base.Visit(identifier);
}
public virtual Evaluant.NLinq.Expressions.Identifier Update(EntityIdentifier entityIdentifier, EntityExpression entity, Evaluant.NLinq.Expressions.Identifier identifier)
{
if (entityIdentifier.Entity != entity || entityIdentifier.Identifier != identifier)
return new EntityIdentifier(identifier, entity);
return entityIdentifier;
}
public override Evaluant.NLinq.Expressions.Expression Visit(Evaluant.NLinq.Expressions.MemberExpression expression)
{
if (getAlias)
{
if (expression.Previous is EntityIdentifier)
{
EntityIdentifier identifier = (EntityIdentifier)expression.Previous;
if (!entityIdentifierAliases.ContainsKey(identifier.Text))
entityIdentifierAliases.Add(identifier.Text, identifier.Entity.Alias);
return identifier;
}
if (expression.Previous != null)
return Visit(expression.Previous);
return base.Visit(expression);
}
if (getPreviousType)
{
if (expression.Previous is EntityIdentifier)
return ((EntityIdentifier)expression.Previous).Entity;
if (expression.Previous != null)
{
EntityExpression entity = (EntityExpression)Visit(expression.Previous);
Model.Reference reference = engine.Factory.Model.Entities[entity.Type].References[((Evaluant.NLinq.Expressions.Identifier)expression.Statement).Text];
entity = new EntityExpression(new TableAlias()) { Type = reference.ChildType, Expression = expression };
return entity;
}
}
if (expression.Statement.ExpressionType == NLinq.Expressions.ExpressionTypes.Call)
{
NLinq.Expressions.MethodCall item = (NLinq.Expressions.MethodCall)expression.Statement;
AggregateFunctionType aggregateType;
switch (item.Identifier.Text)
{
case "Count":
aggregateType = AggregateFunctionType.Count;
break;
case "Average":
aggregateType = AggregateFunctionType.Avg;
break;
case "Max":
aggregateType = AggregateFunctionType.Max;
break;
case "Min":
aggregateType = AggregateFunctionType.Min;
break;
case "Sum":
aggregateType = AggregateFunctionType.Sum;
break;
default:
aggregateType = AggregateFunctionType.Unknown;
break;
}
if (aggregateType == AggregateFunctionType.Unknown)
{
SelectStatement oldSelect = select;
if (item.Identifier.Text == "Take")
{
Visit(expression.Previous);
select.Top = (int)((Constant)item.Parameters[0]).Value;
return select;
}
if (item.Identifier.Text == "Skip")
{
Visit(expression.Previous);
if (Convert.ToInt32(((Constant)item.Parameters[0]).Value) == 0)
return select;
if (select.OrderBy == null)
throw new NotSupportedException("A skip operation cannot be done on a statement which is not ordered");
List<IAliasedExpression> columns = new List<IAliasedExpression>(select.Columns);
columns.Add(new ComplexColumnExpression(null, new RowNumber(select.OrderBy), "rn" + select.Alias));
select.Columns = columns.ToArray();
columns.RemoveAt(columns.Count - 1);
oldSelect = select;
select = new SelectStatement(new TableAlias(), null, new FromClause(select), null, new NLinq.Expressions.WhereClause(new NLinq.Expressions.BinaryExpression(NLinq.Expressions.BinaryExpressionType.Greater, new ColumnExpression(select.Alias, "rn" + select.Alias), item.Parameters[0])));
columns = new List<IAliasedExpression>();
foreach (IAliasedExpression expr in oldSelect.Columns)
{
IAliasedExpression column = null;
if (expr.DbExpressionType == DbExpressionType.Column)
{
column = new ColumnExpression(oldSelect.Alias, ((ColumnExpression)expr).ColumnAlias, ((ColumnExpression)expr).ColumnAlias);
}
else if (expr.DbExpressionType == DbExpressionType.Entity)
{
EntityExpression entity = expr as EntityExpression;
column = new ComplexColumnExpression(oldSelect.Alias, new NLinq.Expressions.MemberExpression(((NLinq.Expressions.MemberExpression)entity.Expression).Statement, entity.Expression));
}
else
throw new NotSupportedException();
if (column != null)
columns.Add(column);
}
if (oldSelect.OrderBy != null && oldSelect.OrderBy.Count > 0)
{
List<Evaluant.NLinq.Expressions.OrderByCriteria> criterias = new List<NLinq.Expressions.OrderByCriteria>();
foreach (var criteria in oldSelect.OrderBy.Criterias)
{
if (criteria.Expression != null)
{
if (criteria.Expression.ExpressionType == NLinq.Expressions.ExpressionTypes.MemberAccess)
{
criterias.Add(new NLinq.Expressions.OrderByCriteria(new ColumnExpression(oldSelect.Alias, (NLinq.Expressions.Identifier)((NLinq.Expressions.MemberExpression)criteria.Expression).Statement), criteria.Ascending));
}
}
}
if (criterias.Count > 0)
select.OrderBy = new NLinq.Expressions.OrderByClause(criterias);
}
//Since we include a surrounding select, we need to clone some information with alias changing
var aliasChanger = new LazyAliasResolver(new Dictionary<TableAlias, TableAlias> { { TableAlias.All, oldSelect.Alias } });
select.Columns = aliasChanger.VisitColumns(columns);
select.OrderBy = aliasChanger.VisitOrderBy(select.OrderBy);
oldSelect.OrderBy = null;
return select;
}
if (item.Identifier.Text == "First")
{
Visit(expression.Previous);
select.Top = 1;
return select;
}
if (item.Identifier.Text == "Last")
{
Visit(expression.Previous);
if (select.OrderBy != null && select.OrderBy.Criterias != null && select.OrderBy.Criterias.Count > 0)
{
foreach (NLinq.Expressions.OrderByCriteria criteria in select.OrderBy.Criterias)
{
criteria.Ascending = !criteria.Ascending;
}
}
else
throw new NotSupportedException("To use Last or LastOrDefault, you have to specify an order in your query.");
select.Top = 1;
return select;
}
if (item.Identifier.Text == "Any")
{
if (expression.Previous.ExpressionType != NLinq.Expressions.ExpressionTypes.Quote)
{
select = new SelectStatement(new TableAlias());
select.Columns = new[] { new ComplexColumnExpression(
null,
new Constant(1, System.Data.DbType.Int32))
};
select.Where = new NLinq.Expressions.WhereClause(Visit(expression.Previous));
var result = new Exists(select);
select = oldSelect;
return result;
}
return new Exists(Visit(expression.Previous));
}
if (item.Identifier.Text == "Distinct")
{
Visit(expression.Previous);
select.Distinct = true;
return select;
}
return expression;
select = new SelectStatement(new TableAlias());
Visit(expression.Previous);
SelectStatement previousSelect = select;
select = oldSelect;
if (item.Parameters.Length == 0)
return new SelectStatement(new TableAlias(), new IAliasedExpression[] { new Aggregate(item.Identifier, ColumnExpression.AllColumns) }, new FromClause(previousSelect), null, null);
else
return new SelectStatement(new TableAlias(), new IAliasedExpression[] { new Aggregate(item.Identifier, item.Parameters) }, new FromClause(previousSelect), null, null);
}
else
{
IAliasedExpression result;
if (expression.Previous is Evaluant.NLinq.Expressions.MemberExpression)
{
//If we are aggregating results
if (select == null)
{
Visit(expression.Previous);
SelectStatement oldSelect = select;
select = new SelectStatement(new TableAlias());
var columns = new IAliasedExpression[] { new Aggregate(aggregateType, new Constant(1, System.Data.DbType.Int32)) };
select.Columns = columns;
select.From = new FromClause(oldSelect);
//Prevent order by if counting (useless, and causes crashes on SQLServer
if (oldSelect.OrderBy != null)
oldSelect.OrderBy = null;
return select;
}
else
{
SelectStatement oldSelect = select;
select = new SelectStatement(new TableAlias());
//from var veryPrevious in oldSelect.From
//from var a in expression.Previous
//where veryPrevious==oldSelect.Select
//select a
getAlias = true;
EntityIdentifier identifier = (EntityIdentifier)Visit(expression);
getAlias = false;
getPreviousType = true;
EntityExpression previousEntity = (EntityExpression)Visit(expression.Previous);
getPreviousType = false;
select.From = oldSelect.From;
Evaluant.NLinq.Expressions.Identifier generatedIdentifier = new Evaluant.NLinq.Expressions.Identifier("source" + expression.GetHashCode());
generatedIdentifier = new EntityIdentifier(generatedIdentifier, new EntityExpression(identifier.Entity.Alias) { Type = previousEntity.Type, Expression = generatedIdentifier });
Evaluant.NLinq.Expressions.Identifier generatedTargetIdentifier = new Evaluant.NLinq.Expressions.Identifier("target" + expression.GetHashCode());
generatedTargetIdentifier = new EntityIdentifier(generatedTargetIdentifier, new EntityExpression(new TableAlias()) { Type = previousEntity.Type, Expression = generatedTargetIdentifier });
//from generatedIdentifier
//from generatedTargetIdentifier in expression
//where generatedIdentifier==identifier
//select generatedTargetIdentifier
//Add a join to load the reference on which we want to aggregate
Evaluant.NLinq.Expressions.QueryExpression query = new Evaluant.NLinq.Expressions.QueryExpression(
new NLinq.Expressions.FromClause(identifier.Entity.Type, generatedIdentifier, null),
new Evaluant.NLinq.Expressions.QueryBody(
new Evaluant.NLinq.Expressions.ClauseList{
new NLinq.Expressions.FromClause(previousEntity.Type, generatedTargetIdentifier, expression.Previous),
new Evaluant.NLinq.Expressions.WhereClause(
new Evaluant.NLinq.Expressions.BinaryExpression(
Evaluant.NLinq.Expressions.BinaryExpressionType.Equal,
new EntityReferenceExpression(((EntityIdentifier)generatedIdentifier).Entity),
new EntityReferenceExpression(identifier.Entity)))
}, new Evaluant.NLinq.Expressions.SelectClause(
new EntityReferenceExpression(((EntityIdentifier)generatedTargetIdentifier).Entity)),
null));
result = (IAliasedExpression)Visit(query);
select = oldSelect;
}
}
else
result = (IAliasedExpression)Visit(expression.Previous);
if (item.Parameters.Length == 0)
result = new SelectStatement(new TableAlias(), new IAliasedExpression[] { new Aggregate(aggregateType, ColumnExpression.AllColumns) }, new FromClause(result), null, null);
else
result = new SelectStatement(new TableAlias(), new IAliasedExpression[] { new Aggregate(aggregateType, item.Parameters) }, new FromClause(result), null, null);
return (NLinq.Expressions.Expression)result;
}
}
return base.Visit(expression);
//throw new NotSupportedException("There should be at least one previous");
}
