internal IQuery BuildQuery(Expression exp)
{
var mainTable = f.Table(_repo);
_query = f.Query(mainTable);
mainTable.Alias = QueryGenerationContext.Get(_query).NextTableAlias();
this.Visit(exp);
return(_query);
}
protected override Expression VisitMethodCall(MethodCallExpression exp)
{
var method = exp.Method;
_isAny = method.Name == LinqConsts.EnumerableMethod_Any;
//先访问表达式 book.ChapterList.Cast<Chapter>()，获取列表属性。
var invoker = exp.Arguments[0];
_parentPropertyFinder.Find(invoker);
var listPropertyTable = _parentPropertyFinder.PropertyOwnerTable;
var listProperty = _parentPropertyFinder.Property as IListProperty;
if (listProperty == null)
{
throw EntityQueryBuilder.OperationNotSupported(invoker);
}
//为该列表对应的实体创建表对象、查询对象。
var childRepo = RepositoryFactoryHost.Factory.FindByEntity(listProperty.ListEntityType);
var childTable = f.Table(childRepo);
_query = f.Query(
from: childTable,
selection: f.Literal("1")
);
var qgc = QueryGenerationContext.Get(_parentQuery);
qgc.Bind(_query);
childTable.Alias = qgc.NextTableAlias();
//Any、All 方法如果有第二个参数，那么第二个参数就是条件表达式。如：c => c.Name == chapterName
if (exp.Arguments.Count == 2)
{
var reverseWhere = !_isAny;//如果是 All，则需要反转里面的所有操作符。
var queryBuilder = new EntityQueryBuilder(childRepo, reverseWhere);
queryBuilder.BuildQuery(exp.Arguments[1], _query);
}
//添加子表查询与父实体的关系条件：WHERE c.BookId = b.Id
var parentProperty = childRepo.FindParentPropertyInfo(true);
var parentRefIdProperty = (parentProperty.ManagedProperty as IRefProperty).RefIdProperty;
var toParentConstraint = f.Constraint(childTable.Column(parentRefIdProperty), listPropertyTable.IdColumn);
_query.Where = f.And(toParentConstraint, _query.Where);
return(exp);
}
//暂时去除
///// <summary>
///// 在查询对象中查找或者创建指定引用属性对应的连接表对象。
///// </summary>
///// <param name="propertyOwner">聚合子属性所在的实体对应的表。也是外键关系中主键表所在的表。</param>
///// <param name="childrenProperty">指定的聚合子属性。</param>
///// <returns></returns>
//internal ITableSource FindOrCreateJoinTable(ITableSource propertyOwner, IListProperty childrenProperty)
//{
// if (childrenProperty.HasManyType != HasManyType.Composition) throw new InvalidProgramException("只能对聚合子属性使用此方法。");
// //先找到这个关系对应的引用属性。
// var refEntityType = childrenProperty.ListEntityType;
// var refRepo = RepositoryFactoryHost.Factory.FindByEntity(refEntityType);
// var parentProperty = refRepo.FindParentPropertyInfo(true);
// var parentRef = (parentProperty.ManagedProperty as IRefProperty).RefIdProperty;
// var refTableSource = _allJoinTables.FirstOrDefault(
// ts => ts.RefProperty == parentRef && ts.PrimaryKeyTable == propertyOwner
// );
// if (refTableSource == null)
// {
// var f = QueryFactory.Instance;
// var fkTable = f.Table(refRepo, QueryGenerationContext.Get(this).NextTableAlias());
// refTableSource = AddJoinTable(fkTable, parentRef, propertyOwner, fkTable);
// }
// return refTableSource.ForeignKeyTable;
//}
/// <summary>
/// 在查询对象中查找或者创建指定引用属性对应的连接表对象。
/// </summary>
/// <param name="propertyOwner">引用属性所在的实体对应的表。也是外键关系中外键列所在的表。</param>
/// <param name="refProperty">指定的引用属性。</param>
/// <returns></returns>
internal ITableSource FindOrCreateJoinTable(ITableSource propertyOwner, IRefEntityProperty refProperty)
{
var refTableSource = _allJoinTables.FirstOrDefault(
ts => ts.ForeignKeyTable == propertyOwner && ts.RefProperty == refProperty
);
if (refTableSource == null)
{
var f = QueryFactory.Instance;
var refEntityType = refProperty.RefEntityType;
var refRepo = RepositoryFactoryHost.Factory.FindByEntity(refEntityType);
var pkTable = f.Table(refRepo, QueryGenerationContext.Get(this).NextTableAlias());
refTableSource = AddJoinTable(propertyOwner, refProperty, pkTable, pkTable);
}
return(refTableSource.PrimaryKeyTable);
}
