internal bool IsInnerJoin(DB3 firstTable)
{
if (IsRefTable(firstTable))
{
return(true);
}
return(!DbMapping.GetColumnMap(FKColumns[0]).IsNullable);
}
internal Column[] GetFK(int alias)
{
List <Column> columns = new List <Column>();
foreach (var columnID in FKColumns)
{
columns.Add(Designer.Identifier(alias.ToString(), DbMapping.GetColumnMap(columnID).Name.Part1));
}
return(columns.ToArray());
}
internal string BuildRelation(DB3 table1, string alias1, string alias2)
{
string aliasA, aliasB;
if (table1.TableID.Equals(ID.TableID) &&
!IsSelfRelation)
{
aliasA = alias1;
aliasB = alias2;
}
else
{
aliasA = alias2;
aliasB = alias1;
}
var sql = Text.GenerateSql(70);
for (int i = 0; i < FKColumns.Count(); ++i)
{
if (i > 0)
{
sql.Append(Text._And_);
}
var columnA = DbMapping.GetColumnMap(FKColumns[i]);
var columnB = DbMapping.GetColumnMap(RefColumns[i]);
sql
.AppendFormat("[{0}].{1} = [{2}].{3}",
aliasA, columnA.Name.Sql,
aliasB, columnB.Name.Sql);
}
return(sql.ToString());
}
// When a subject S2 of a predicate is a single node without the chaining and the predicates (+expression)
// and it represents a simple foreign key (with a single column) then it is translated as an expression
// where FK attribute is checked by NOT NULL operator.
// note:
// If a FK is NOT NULLABLE then the .Where method is omitted.
// returns:
// True if a simple foreign key has been processed.
internal static bool ProcessSimpleForeignKey(
DbNode currentNode,
DbNode innerNode,
Predicate predicate,
Link link,
ref Chainer query)
{
if (!(
innerNode.IsLast && // subject is a single non-chained node
!((IPredicate)innerNode).HasPredicate && // without a predicate
!innerNode.HasExpression // without expression
))
{
return(false);
}
var foreignKey = innerNode.GetFK();
var relation = link.TryGetRelation(foreignKey);
// is relation many-to-one?
if (relation.IsRefTable(currentNode.SynonymOrThis.NodeID))
{
return(false);
}
// is simple foreign key?
if (relation.FKColumns.Count() > 1)
{
return(false);
}
// assure that foreign key column is given
if (foreignKey.IsDefault)
{
foreignKey = relation.ForeignKey;
}
var fk = DbMapping.GetColumnMap(foreignKey);
var column = String.Format("{0}.{1}", predicate.Subject.Index, fk.Name.Part1);
// prepare expression
Expression expression = column.IsNotNull();
if (!fk.IsNullable)
{
expression = "1=1";
}
if (query is ConditionChainer)
{
if (predicate.LogicalOperator == LogicalOperator.Or)
{
query = ((ConditionChainer)query)
.OrWhere(expression, predicate.Sign, predicate.PredicateGroup);
}
else
{
query = ((ConditionChainer)query)
.AndWhere(expression, predicate.Sign, predicate.PredicateGroup);
}
}
else
{
query = ((IWhere)query)
.Where(expression, predicate.Sign, predicate.PredicateGroup);
}
return(true);
}
