Changes between Version 38 and Version 39 of FDORfc50

Timestamp:

07/13/10 05:38:16 (15 years ago)

Author:

romicadascalescu

Comment:

--

FDORfc50

@@ -148 +148 @@
       enum FdoJoinType
       {
-          /// default join type. 
-          FdoJoinType_None = 0x01,
+          /// default join type. This value can be returned by the GetJoinTypes()
+          /// in case joins are not supported
+          /// rather than provider throw an exception can return this value
+          /// in case join are not  supported (this is like NAN for doubles)
+          FdoJoinType_None = 0x00,
           /// inner join
-          FdoJoinType_Inner = 0x02,
+          FdoJoinType_Inner = 0x01,
           /// right outer join
-          FdoJoinType_RightOuter = 0x04,
+          FdoJoinType_RightOuter = 0x02,
           /// left outer join
-          FdoJoinType_LeftOuter = 0x08,
+          FdoJoinType_LeftOuter = 0x04,
           /// full outer join
-          FdoJoinType_FullOuter = 0x10,
-          /// cross join
-          FdoJoinType_Cross = 0x20
+          FdoJoinType_FullOuter = 0x08,
+          /// cross join (cartesian join)
+          /// can be used for cases like SELECT * FROM A, B
+          FdoJoinType_Cross = 0x10
       };
 }}}
 
 We need to add two new methods in connection capabilities: supports join selects (to avoid an exception when a user will try to use the new method from FdoISelect) and also supported join types which can be a collection or a value as OR between values, since all join types cannot be more than we can fit in a int32 using OR e.g.: val1|val2. We need to add an extra capability named !SupportsSubSelects() since sub-select will be handled in filter side and applications might need a way to detect if it will allow users to create sub-selects in filter.
+GetJoinTypes() will return FdoJoinType_None in case no join is supported. 
+Since we can detect if a connection can support joins using GetJoinTypes() then SupportsJoins() can be removed or can be implemented as SupportsJoins(){return (GetJoinTypes() != 0);}
 
 {{{
@@ -253 +259 @@
 
       FdoPtr<FdoIdentifier> fcname2 = FdoIdentifier::Create(L"class2");
-      FdoPtr<FdoJoinCriteria> jc1 = FdoJoinCriteria::Create(L"p2", fcname2, FdoJoinType_None);
+      FdoPtr<FdoJoinCriteria> jc1 = FdoJoinCriteria::Create(L"p2", fcname2, FdoJoinType_Cross);
       jcrits->Add(jc1);