internal ColumnAlias(DbmsRelationTree table, DbmsColumn column)
{
_Table = table;
_Column = column;
_IsUniqueName = false;
_Alias = null;
}
private string BuildJoinClause(DbmsRelationTree startTable)
{
StringBuilder joinClause = new StringBuilder();
joinClause.AppendFormat(startTable.QualifiedName);
joinClause.Append(" ");
joinClause.AppendLine(startTable.LinkProperty.Alias);
foreach (DbmsForeignKey fk in startTable.ForeignKeys) // INNER JOIN first
{
if (!fk.IsNullable) // ForeignKeyColumns is not null
{
AppendJoinSource(joinClause, fk);
}
}
foreach (DbmsForeignKey fk in startTable.ForeignKeys) // Then LEFT JOIN
{
if (fk.IsNullable) // ForeignKeyColumns is nullable
{
AppendJoinSource(joinClause, fk);
}
}
return(joinClause.ToString());
}
public DbmsForeignKey(string constraintName,
DbmsRelationTree foreignKeyBaseTable, string primaryUniqueKeyBaseTableName)
{
_ConstraintName = constraintName;
_ForeignKeyBaseTable = foreignKeyBaseTable;
_PrimaryUniqueKeyBaseTable = new DbmsRelationTree(primaryUniqueKeyBaseTableName, this);
_ForeignKeyColumns = new List <DbmsColumn>();
_PrimaryUniqueKeyColumns = new List <DbmsColumn>();
}
private void TraverseRelationTree(DbmsRelationTree nodeTable, string parentAlias, byte position)
{
nodeTable.LinkProperty = new TableLink(this, parentAlias, position);
foreach (DbmsColumn col in nodeTable.DisplayColumns)
{
_ColumnAliases.Add(new ColumnAlias(nodeTable, col));
}
for (byte pos = 0; pos < nodeTable.ForeignKeys.Count; pos++)
{
TraverseRelationTree(nodeTable.ForeignKeys[pos].PrimaryUniqueKeyBaseTable, nodeTable.LinkProperty.Alias, pos);
}
}
public bool DetectLoopback() // Call after the node has been added into the tree
{
DbmsForeignKey parentForeignKey;
for (DbmsRelationTree baseTable = this.ForeignKeyBaseTable; ; baseTable = parentForeignKey.ForeignKeyBaseTable)
{
parentForeignKey = baseTable.ParentForeignKey;
if (parentForeignKey == null)
{
break;
}
if (_ConstraintName.Equals(parentForeignKey.ConstraintName, System.StringComparison.OrdinalIgnoreCase))
{
return(true);
}
}
return(false);
}
internal JoinedTable(DbmsRelationTree rootTable)
{
_RootTable = rootTable;
_ColumnAliases = new List <ColumnAlias>();
TraverseRelationTree(rootTable, string.Empty, 0);
}
