public Where(IXTable source, IExpression expression) : base(source)
{
_expression = expression;
// Build a mapper to hold matching rows and remap source arrays
_mapper = new RowRemapper();
// Build wrapper columns
_columns = new RemappedColumn[source.Columns.Count];
for (int i = 0; i < _columns.Length; ++i)
{
_columns[i] = new RemappedColumn(source.Columns[i], _mapper);
}
}
public Join(IXTable source, string joinFromColumn, IXTable joinToSource, string joinToColumn, string joinSidePrefix)
{
if (source == null)
{
throw new ArgumentNullException("source");
}
_source = source;
_joinToSource = joinToSource;
// Request the JoinFromColumn Getter
IXColumn joinFrom = source.Columns.Find(joinFromColumn);
_joinColumnType = joinFrom.ColumnDetails.Type;
_joinFromColumnGetter = joinFrom.CurrentGetter();
// Request the JoinToColumn Reader (we'll need it cached)
_joinToColumn = _joinToSource.Columns.Find(joinToColumn);
Type joinToColumnType = _joinToColumn.ColumnDetails.Type;
if (joinToColumnType != _joinColumnType)
{
throw new ArgumentException($"Join requires columns of matching types; join from {_joinColumnType.Name} to {joinToColumnType.Name} not supported.");
}
_joinToSeekGetter = _joinToColumn.SeekGetter();
// Build a remapper for left side columns
_sourceJoinedRowsFilter = new RowRemapper();
// Build column wrappers
_columns = new IXColumn[source.Columns.Count + joinToSource.Columns.Count];
_rightSideColumns = new SeekedColumn[joinToSource.Columns.Count];
// Left Side columns are filtered to rows that joined (inner join)
for (int i = 0; i < source.Columns.Count; ++i)
{
_columns[i] = new RemappedColumn(source.Columns[i], _sourceJoinedRowsFilter);
}
// Right side columns are seeked to the right side matching rows
for (int i = 0; i < joinToSource.Columns.Count; ++i)
{
SeekedColumn column = new SeekedColumn(RenamedColumn.Build(joinToSource.Columns[i], joinSidePrefix + joinToSource.Columns[i].ColumnDetails.Name));
_rightSideColumns[i] = column;
_columns[i + source.Columns.Count] = column;
}
}
