/// <summary>
/// Expand one attribute by building its path segments as dimension objects.
/// Use the provided list of attributes for expansion recursively. This list essentially represents a schema.
/// Also, adjust path names in special cases like empty name or simple structure.
/// </summary>
public void ExpandAttribute(List <ColumnAtt> attributes, List <DcColumn> columns) // Add and resolve attributes by creating dimension structure from FKs
{
ColumnAtt att = this;
if (att.Segments.Count > 0)
{
return; // Already expanded (because of recursion)
}
bool isKey = !string.IsNullOrEmpty(att.RelationalPkName) || att.IsKey;
if (string.IsNullOrEmpty(att.RelationalFkName)) // No FK - primitive column - end of recursion
{
// Find or create a primitive dim segment
DcColumn seg = columns.FirstOrDefault(c => c.Input == att.Input && StringSimilarity.SameColumnName(((ColumnRel)c).RelationalFkName, att.RelationalFkName));
if (seg == null)
{
seg = new ColumnRel(att.RelationalColumnName, att.Input, att.Output, isKey, false); // Maybe copy constructor?
((ColumnRel)seg).RelationalFkName = att.RelationalFkName;
columns.Add(seg);
}
att.InsertLast(seg); // add it to this attribute as a single segment
}
else
{ // There is FK - non-primitive column
// Find target set and target attribute (name resolution)
ColumnAtt tailAtt = attributes.FirstOrDefault(a => StringSimilarity.SameTableName(a.Input.Name, att.RelationalTargetTableName) && StringSimilarity.SameColumnName(a.Name, att.RelationalTargetColumnName));
DcTable gTab = tailAtt.Input;
// Find or create a dim segment
DcColumn seg = columns.FirstOrDefault(c => c.Input == att.Input && StringSimilarity.SameColumnName(((ColumnRel)c).RelationalFkName, att.RelationalFkName));
if (seg == null)
{
seg = new ColumnRel(att.RelationalFkName, att.Input, gTab, isKey, false);
((ColumnRel)seg).RelationalFkName = att.RelationalFkName;
columns.Add(seg);
}
att.InsertLast(seg); // add it to this attribute as first segment
//
// Recursion. Expand tail attribute and add all segments from the tail attribute (continuation)
//
tailAtt.ExpandAttribute(attributes, columns);
att.InsertLast(tailAtt);
// Adjust name. How many attributes belong to the same FK as this attribute (FK composition)
List <ColumnAtt> fkAtts = attributes.Where(a => a.Input == att.Input && StringSimilarity.SameColumnName(att.RelationalFkName, a.RelationalFkName)).ToList();
if (fkAtts.Count == 1)
{
seg.Name = att.RelationalColumnName; // Adjust name. For 1-column FK, name of the FK-dim is the column name (not the FK name)
}
}
}
private void FillEntriesTypes()
{
// Change available target type lists for each source column without changing the list itself
// If some current type is not present in the new schema then deselect this entry
// If an entry is selected then it must have some type selected (it is error if an entry does not have a selected type)
List <DcTable> targetTypes = GetSchemaTypes();
DcTable defaultType = null;
foreach (DcTable table in targetTypes)
{
if (StringSimilarity.SameTableName(table.Name, "String"))
{
defaultType = table;
break;
}
}
foreach (ColumnMappingEntry entry in Entries)
{
entry.TargetTypes.Clear();
targetTypes.ForEach(x => entry.TargetTypes.Add(x));
// Now find a good new match for the current type
// In fact, it should be done by some automatic matching procedure for inter-schema primitive matches
// Target type has been selected. Try to find the same type
if (entry.TargetType != null)
{
DcTable targetType = null;
foreach (DcTable table in targetTypes)
{
if (StringSimilarity.SameTableName(table.Name, entry.TargetType.Name))
{
targetType = table;
break; // Found
}
}
if (targetType != null) // Found
{
entry.TargetType = targetType;
continue;
}
}
// Either not selected or not found. Try to select the source type
if (entry.Source.Output != null)
{
DcTable targetType = null;
foreach (DcTable table in targetTypes)
{
if (StringSimilarity.SameTableName(table.Name, entry.Source.Output.Name))
{
targetType = table;
break; // Found
}
}
if (targetType != null) // Found
{
entry.TargetType = targetType;
continue;
}
}
// Nothing helps
entry.TargetType = defaultType;
}
}