protected override Expression VisitBinary(BinaryExpression binaryExp)
{
if (binaryExp.NodeType == ExpressionType.AndAlso || binaryExp.NodeType == ExpressionType.OrElse)
{
//先计算左边的约束结果
this.Visit(binaryExp.Left);
this.MakeBooleanConstraintIfNoValue();
var left = _query.Where;
//再计算右边的约束结果
this.Visit(binaryExp.Right);
this.MakeBooleanConstraintIfNoValue();
var right = _query.Where;
//使用 AndOrConstraint 合并约束的结果。
var op = binaryExp.NodeType == ExpressionType.AndAlso ?
BinaryOperator.And : BinaryOperator.Or;
if (_reverseWhere)
{
op = binaryExp.NodeType == ExpressionType.AndAlso ? BinaryOperator.Or : BinaryOperator.And;
}
_query.Where = f.Binary(left, op, right);
}
else
{
this.VisitPropertyComparison(binaryExp);
}
return(binaryExp);
}
/// <summary>
/// <![CDATA[
/// 将聚合子表达式解析为嵌入式子查询条件。
/// 例如：
/// 将表达式
/// book.ChapterList.Cast<Chapter>().Any(c => c.Name == chapterName)
/// 转换为：
/// f.Exists(f.Query(chapter,
/// where: f.And(
/// f.Constraint(chapter.Column(Chapter.BookIdProperty), book.IdColumn),
/// f.Constraint(chapter.Column(Chapter.NameProperty), chapterName)
/// )
/// ))
/// SQL：
/// SELECT * FROM [Book] b
/// WHERE EXISTS(
/// SELECT * FROM [Chapter] c
/// WHERE c.BookId = b.Id AND
/// c.Name = {0}
/// )
/// ]]>
/// </summary>
/// <param name="exp">需要解析的表达式</param>
/// <param name="parentQuery"></param>
/// <param name="propertyFinder">The property finder.</param>
internal IConstraint Build(Expression exp, IQuery parentQuery, PropertyFinder propertyFinder)
{
_parentQuery = parentQuery;
_parentPropertyFinder = propertyFinder;
this.Visit(exp);
var res = f.Exists(_query);
if (!_isAny)
{
res = f.Not(res);
}
//如果父查询中需要反转条件，则返回 NOT 语句。
if (propertyFinder.ReverseConstraint)
{
res = f.Not(res);
}
//把可空外键的不可空条件，与 Exists 条件合并后返回。
if (propertyFinder.NullableRefConstraint != null)
{
var op = propertyFinder.ReverseConstraint ? BinaryOperator.Or : BinaryOperator.And;
res = f.Binary(propertyFinder.NullableRefConstraint, op, res);
}
return(res);
}
protected override void VisitAndOrConstraint(AndOrConstraint node)
{
this.Visit(node.Left);
var leftWhere = _whereResult;
this.Visit(node.Right);
var rightWhere = _whereResult;
_whereResult = f.Binary(leftWhere, node.IsAnd ? BinaryOperator.And : BinaryOperator.Or, rightWhere);
}
private void DealBracket(string part)
{
if (part == "(")
{
if (_concat.HasValue && _current != null)
{
_bracketStack.Push(new StackItem
{
Concat = _concat.Value,
Constraint = _current
});
_concat = null;
_current = null;
}
}
else
{
if (_bracketStack.Count > 0)
{
var outBracket = _bracketStack.Pop();
_current = _f.Binary(outBracket.Constraint, outBracket.Concat, _current);
}
}
}