|
public ChangeOrderBy ( IEnumerable |
||
| orderBy | IEnumerable |
|
| Результат | ||
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (selectExpression.OrderBy != null)
{
return selectExpression.ChangeOrderBy(null);
}
return base.VisitSelect(selectExpression);
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (selectExpression.Skip != null)
{
var rowNumber = new SqlFunctionCallExpression(typeof(int), "ROW_NUMBER");
var oldAliases = (selectExpression.From as ISqlExposesAliases)?.Aliases;
var innerSelectWithRowAlias = selectExpression.Alias + "_ROW";
var cols = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, selectExpression.Alias, c.Name))).ToList();
var over = new SqlOverExpression(rowNumber, selectExpression.OrderBy?.ToReadOnlyCollection() ?? cols.Select(c => new SqlOrderByExpression(OrderType.Ascending, c.Expression)).ToReadOnlyCollection());
if (oldAliases != null)
{
over = (SqlOverExpression)AliasReferenceReplacer.Replace(over, oldAliases.Contains, selectExpression.Alias);
}
var rowColumn = new SqlColumnDeclaration(RowColumnName, over);
cols.Add(rowColumn);
var innerSelectWithRowColumns = cols.ToReadOnlyCollection();
var innerSelectWithRow = new SqlSelectExpression(selectExpression.Type, innerSelectWithRowAlias, innerSelectWithRowColumns, this.Visit(selectExpression.ChangeOrderBy(null).ChangeSkipTake(null, null)), null, null, null, false, null, null, false);
var outerColumns = selectExpression.Columns.Select(c => new SqlColumnDeclaration(c.Name, new SqlColumnExpression(c.Expression.Type, innerSelectWithRowAlias, c.Name)));
Expression rowPredicate = Expression.GreaterThan(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), selectExpression.Skip);
if (selectExpression.Take != null && !(selectExpression.Take is SqlTakeAllValueExpression))
{
rowPredicate = Expression.And
(
rowPredicate,
Expression.LessThanOrEqual(new SqlColumnExpression(typeof(int), innerSelectWithRowAlias, rowColumn.Name), Expression.Add(selectExpression.Skip, selectExpression.Take))
);
}
var retval = new SqlSelectExpression(selectExpression.Type, selectExpression.Alias, outerColumns.ToReadOnlyCollection(), innerSelectWithRow, rowPredicate, null, null, selectExpression.Distinct, null, null, selectExpression.ForUpdate, selectExpression.Reverse, selectExpression.Into);
return retval;
}
return base.VisitSelect(selectExpression);
}
protected override Expression VisitSelect(SqlSelectExpression selectExpression)
{
if (this.currentProjection == null || this.currentProjection.Select != selectExpression)
{
return base.VisitSelect(selectExpression);
}
var objectType = selectExpression.Type.GetSequenceElementType();
if (!objectType.IsDataAccessObjectType())
{
return base.VisitSelect(selectExpression);
}
var aliasesAndTypes = SqlAliasTypeCollector.Collect(selectExpression)
.ToDictionary(c => c.Item1, c => typeDescriptorProvider.GetTypeDescriptor(c.Item2.GetSequenceElementType() ?? c.Item2));
List<SqlOrderByExpression> orderBys = null;
var includeJoins = selectExpression.From.GetIncludeJoins().ToList();
List<SqlColumnExpression> leftMostColumns = null;
foreach (var includeJoin in includeJoins)
{
var equalsExpression = (BinaryExpression)SqlExpressionFinder.FindFirst(includeJoin, c => c.NodeType == ExpressionType.Equal);
var left = (SqlColumnExpression)equalsExpression.Left;
var right = (SqlColumnExpression)equalsExpression.Right;
var leftType = aliasesAndTypes[left.SelectAlias];
var rightType = aliasesAndTypes[right.SelectAlias];
if (leftMostColumns == null)
{
var typeDescriptor = this.typeDescriptorProvider.GetTypeDescriptor(objectType);
var primaryKeyColumns = new HashSet<string>(QueryBinder.GetPrimaryKeyColumnInfos(this.typeDescriptorProvider, typeDescriptor).Select(c => c.ColumnName));
leftMostColumns = primaryKeyColumns
.Select(c => new SqlColumnExpression(objectType, left.SelectAlias, c))
.ToList();
}
var rightProperty = rightType.GetPropertyDescriptorByColumnName(right.Name);
var leftProperty = rightProperty.RelationshipInfo?.TargetProperty ?? leftType.GetPropertyDescriptorByColumnName(left.Name);
if (leftProperty.PropertyType.GetGenericTypeDefinitionOrNull() == typeof(RelatedDataAccessObjects<>))
{
var rightColumns = SqlExpressionFinder.FindAll(includeJoin, c => c.NodeType == (ExpressionType)SqlExpressionType.Column && ((SqlColumnExpression)c).SelectAlias == right.SelectAlias);
var leftColumns = SqlExpressionFinder.FindAll(includeJoin, c => c.NodeType == (ExpressionType)SqlExpressionType.Column && ((SqlColumnExpression)c).SelectAlias == left.SelectAlias);
if (orderBys == null)
{
orderBys = new List<SqlOrderByExpression>();
if (selectExpression.OrderBy?.Count > 0)
{
orderBys.AddRange(selectExpression.OrderBy);
orderBys.AddRange(leftMostColumns.Select(c => new SqlOrderByExpression(OrderType.Ascending, c)));
}
}
orderBys.AddRange(rightColumns.Select(c => new SqlOrderByExpression(OrderType.Ascending, c)));
orderBys.AddRange(leftColumns.Select(c => new SqlOrderByExpression(OrderType.Ascending, c)));
}
}
return selectExpression.ChangeOrderBy(orderBys?.Distinct(SqlExpressionEqualityComparer<SqlOrderByExpression>.Default) ?? selectExpression.OrderBy);
}