private static IDbSelectable CreateNewSelectableForWrappingSelect(
IDbSelect dbSelect, IDbSelectable selectable, DbReference dbRef, Expression m,
IDbObjectFactory dbFactory, UniqueNameGenerator nameGenerator)
{
if (dbRef == null)
{
return(selectable);
}
var oCol = selectable as IDbColumn;
if (oCol != null)
{
return(dbFactory.BuildColumn(dbRef, oCol.GetAliasOrName(), oCol.ValType));
}
var oRefCol = selectable as IDbRefColumn;
if (oRefCol != null)
{
return(dbFactory.BuildRefColumn(dbRef, oRefCol.Alias, oRefCol));
}
if (selectable is IDbFunc oDbFunc)
{
if (string.IsNullOrEmpty(oDbFunc.Alias))
{
oDbFunc.Alias = nameGenerator.GenerateAlias(dbSelect, oDbFunc.Name, true);
}
return(dbFactory.BuildColumn(dbRef, oDbFunc.Alias, oDbFunc.ReturnType));
}
return(dbFactory.BuildColumn(dbRef, selectable.Alias, typeof(string)));
}
private static void UpdateIncludeSelectAndProcessToNodes(
IncludeNode graphNode, IDbSelect includedSelect, IModelInfoProvider infoProvider,
IDbObjectFactory dbFactory, UniqueNameGenerator nameGenerator, AbstractMethodTranslator[] addons)
{
// create temp table
var entityRef = includedSelect.GetReturnEntityRef();
var returnTable = (IDbTable)entityRef.Referee;
var newIncludedSelect = dbFactory.BuildSelect(returnTable);
newIncludedSelect.From.Alias = nameGenerator.GenerateAlias(newIncludedSelect, returnTable.TableName);
var tempTableName = TranslationConstants.TempTablePreix + nameGenerator.GenerateAlias(null, returnTable.TableName, true);
var tempTable = dbFactory.BuildTempTable(tempTableName, includedSelect);
var tempSelect = dbFactory.BuildSelect(tempTable);
tempSelect.From.Alias = nameGenerator.GenerateAlias(tempSelect, tempTable.TableName);
var joinToTemp = MakeJoin(newIncludedSelect, tempSelect, dbFactory, nameGenerator);
var joinTo = joinToTemp.To;
newIncludedSelect.Joins.Add(joinToTemp);
foreach (var pk in returnTable.PrimaryKeys)
{
var fromPkCol = dbFactory.BuildColumn(entityRef, pk.Name, pk.ValType);
includedSelect.Selection.Add(fromPkCol);
var toPkCol = dbFactory.BuildColumn(tempSelect.From, pk.Name, pk.ValType);
tempSelect.Selection.Add(toPkCol);
tempSelect.GroupBys.Add(toPkCol);
toPkCol = dbFactory.BuildColumn(joinTo, pk.Name, pk.ValType);
var binary = dbFactory.BuildBinary(fromPkCol, DbOperator.Equal, toPkCol);
joinToTemp.Condition = joinToTemp.Condition.UpdateBinary(binary, dbFactory);
}
var orderCol = dbFactory.BuildColumn(tempSelect.From, tempTable.RowNumberColumnName, typeof(int));
tempSelect.Selection.Add(orderCol);
orderCol = dbFactory.BuildColumn(joinTo, tempTable.RowNumberColumnName, typeof(int));
newIncludedSelect.OrderBys.Add(orderCol);
graphNode.Select = newIncludedSelect;
graphNode.TempTable = tempTable;
foreach (var toNode in graphNode.ToNodes)
{
TranslateGraphNode(toNode, infoProvider, dbFactory, nameGenerator, addons);
}
}
public static IDbSelect Map(
IDbSelect dbSelect, Type returnType,
IModelInfoProvider infoProvider, IDbObjectFactory dbFactory, UniqueNameGenerator nameGenerator)
{
// If the select returns specified columns, it means there is a constructor in Select,
// e.g (.Select(d => new { A = d.ABC }))
// In this case we do not need to add alias to the end result as where will be one in the select
if (dbSelect.Selection.Any(s => !(s is IDbRefColumn)))
{
return(dbSelect);
}
var entityInfo = infoProvider.FindEntityInfo(returnType);
if (!entityInfo.RequirePropertyNameMapping())
{
return(dbSelect);
}
var alias = nameGenerator.GenerateAlias(dbSelect, TranslationConstants.SubSelectPrefix, true);
var newSelectRef = dbFactory.BuildRef(dbSelect, alias);
var newSelect = dbFactory.BuildSelect(newSelectRef);
foreach (var fieldInfo in entityInfo.Columns)
{
var column = dbFactory.BuildColumn(
newSelectRef, fieldInfo.DbName, fieldInfo.ValType, fieldInfo.PropertyName);
newSelect.Selection.Add(column);
}
return(newSelect);
}
private static IDbSelectable CreateNewSelectableForWrappingSelect(
IDbSelectable selectable, DbReference dbRef, IDbObjectFactory dbFactory)
{
if (dbRef == null)
{
return(selectable);
}
var oCol = selectable as IDbColumn;
if (oCol != null)
{
return(dbFactory.BuildColumn(dbRef, oCol.GetAliasOrName(), oCol.ValType));
}
var oRefCol = selectable as IDbRefColumn;
if (oRefCol != null)
{
return(dbFactory.BuildRefColumn(dbRef, oRefCol.Alias, oRefCol));
}
return(dbFactory.BuildColumn(dbRef, selectable.Alias, typeof(string)));
}
/// <summary>
/// Add selectable into the selection of the select which referred by the ref column.
/// If the ref column has a RefTo ref column, this function will also recursively add
/// the selectable to RefTo ref columns
/// </summary>
public static void AddToReferedSelect(
this IDbRefColumn refCol, IDbObjectFactory factory, string colName, DbType colType, string alias = null)
{
if (refCol.RefTo != null)
{
refCol.RefTo.AddToReferedSelect(factory, colName, colType, alias);
colName = alias ?? colName;
}
var column = factory.BuildColumn(refCol.Ref, colName, colType, alias);
var selection = refCol.OwnerSelect.Selection;
selection.Remove(refCol);
selection.Add(column);
}
protected override Expression VisitMember(MemberExpression m)
{
var expression = Visit(m.Expression);
if (expression is ConstantExpression constExpr)
{
var container = constExpr.Value;
var member = m.Member;
object value = null;
var valueRetrieved = false;
switch (member)
{
case FieldInfo field:
value = field.GetValue(container);
valueRetrieved = true;
break;
case PropertyInfo prop:
value = prop.GetValue(container, null);
valueRetrieved = true;
break;
}
if (valueRetrieved)
{
var dbObject = _dbFactory.BuildConstant(value, true);
_state.ResultStack.Push(dbObject);
return(m);
}
}
var typeInfo = m.Type.GetTypeInfo();
if (m.Expression.Type.IsAnonymouse())
{
var dbRef = (DbReference)_state.ResultStack.Peek();
if (dbRef.RefSelection.ContainsKey(m.Member.Name))
{
var dbObj = dbRef.RefSelection[m.Member.Name];
// pop out the dbRef from the stack, it was the result of
// translate a parameter, and it is not required for following translation
_state.ResultStack.Pop();
_state.ResultStack.Push(dbObj);
return(m);
}
}
if (m.Expression.Type.IsGrouping())
{
var dbRef = (DbReference)_state.ResultStack.Pop();
var dbSelect = dbRef.OwnerSelect;
if (dbSelect.GroupBys.IsSingleKey)
{
var kColumn = dbSelect.GroupBys.Single();
_state.ResultStack.Push(kColumn);
}
else
{
_state.ResultStack.Push(dbRef);
}
return(m);
}
// if the member is a queryable entity, we need to translate it
// into a relation, which means a join
var entityInfo = _infoProvider.FindEntityInfo(m.Type);
if (entityInfo != null)
{
var dbObj = _state.ResultStack.Pop();
var refCol = dbObj as IDbRefColumn;
var fromRef = refCol != null ? refCol.Ref : (DbReference)dbObj;
var fromEntity = _infoProvider.FindEntityInfo(m.Expression.Type);
var relation = fromEntity.GetRelation(m.Member.Name);
var dbJoin = GetOrCreateJoin(relation, fromRef, refCol ?? fromRef.ReferredRefColumn);
// RefColumnAlias is used as alias in case we need to create a ref column for this dbRef
dbJoin.To.RefColumnAlias = m.Member.Name;
if (refCol != null)
{
refCol = _dbFactory.BuildRefColumn(dbJoin.To, m.Member.Name);
if (dbJoin.To.Referee is IDbSelect subSelect)
{
refCol.RefTo = subSelect.Selection.OfType <IDbRefColumn>().Single();
}
_state.ResultStack.Push(refCol);
return(m);
}
_state.ResultStack.Push(relation.IsChildRelation ? dbJoin.To.Referee : dbJoin.To);
return(m);
}
if (typeInfo.Namespace.StartsWith("System"))
{
var dbObj = _state.ResultStack.Pop();
var refCol = dbObj as IDbRefColumn;
var dbRef = refCol != null ? refCol.Ref : (DbReference)dbObj;
var fieldInfo = _infoProvider.FindFieldInfo(m.Member);
var col = _dbFactory.BuildColumn(dbRef, fieldInfo.DbName, fieldInfo.ValType);
_state.ResultStack.Push(col);
// if we create a column whose DbRef is using by a RefColumn
// we need to make sure the column is added to the ref column's owner select
// This normally happen when we are accessing a column from a child relation
refCol = refCol ?? dbRef.ReferredRefColumn;
// if the ref column is not now, and it is referring another ref column
// we need to make sure the column we translated is in the sub select which
// owns the ref column that referred by the current refColumn
refCol?.RefTo?.AddToReferedSelect(_dbFactory, fieldInfo.DbName, fieldInfo.ValType);
return(m);
}
return(base.VisitMember(m));
}
private static void UpdateFromNodeTempTable(
IncludeNode fromNode, IDbObject dbObject, IDbSelect includedSelect,
IDbObjectFactory dbFactory, UniqueNameGenerator nameGenerator)
{
var fromSelect = fromNode.Select;
var dbJoin = fromSelect.Joins.Single(
j => dbObject is DbReference ? ReferenceEquals(j.To, dbObject) : ReferenceEquals(j.To.Referee, dbObject));
// remove the join to included relation from fromSelect
fromSelect.Joins.Remove(dbJoin);
if (dbObject is IDbSelect)
{
var refCol = includedSelect.Selection.Single(c => c is IDbRefColumn);
includedSelect.Selection.Remove(refCol);
}
var keys = dbJoin.Condition.GetDbObjects <IDbColumn>().ToArray();
var fromKeys = keys.Where(c => !ReferenceEquals(c.Ref, dbJoin.To)).ToArray();
var toKeys = keys.Where(c => ReferenceEquals(c.Ref, dbJoin.To)).ToArray();
var tempTable = fromNode.TempTable;
var sourceSelect = tempTable.SourceSelect;
var fromRef = sourceSelect.GetReturnEntityRef();
var returnRef = includedSelect.GetReturnEntityRef();
var tempSelect = dbFactory.BuildSelect(tempTable);
tempSelect.From.Alias = nameGenerator.GenerateAlias(tempSelect, tempTable.TableName);
var joinToTemp = MakeJoin(includedSelect, tempSelect, dbFactory, nameGenerator);
includedSelect.Joins.Add(joinToTemp);
for (var i = 0; i < fromKeys.Length; i++)
{
var fromKey = fromKeys[i];
var toKey = toKeys[i];
var fromPkCol = dbFactory.BuildColumn(fromRef, fromKey.Name, fromKey.ValType);
sourceSelect.Selection.Add(fromPkCol);
var tempPkCol = dbFactory.BuildColumn(tempSelect.From, fromKey.Name, fromKey.ValType);
tempSelect.Selection.Add(tempPkCol);
tempSelect.GroupBys.Add(tempPkCol);
if (dbObject is IDbSelect)
{
var key = toKey;
toKey = (IDbColumn)includedSelect.Selection.Single(c => c.GetAliasOrName() == key.GetNameOrAlias());
includedSelect.Selection.Remove(toKey);
includedSelect.GroupBys.Remove(toKey);
}
fromPkCol = dbFactory.BuildColumn(joinToTemp.To, fromKey.Name, fromKey.ValType);
var toPkCol = dbFactory.BuildColumn(returnRef, toKey.Name, toKey.ValType);
var binary = dbFactory.BuildBinary(toPkCol, DbOperator.Equal, fromPkCol);
joinToTemp.Condition = joinToTemp.Condition.UpdateBinary(binary, dbFactory);
}
}