/// <remarks> Scan range keys are inclusive. </remarks>
public Scan(ServerProcess AProcess, TableBuffer ATable, TableBufferIndex AAccessPath, ScanDirection ADirection, Row AFirstKey, Row ALastKey)
{
FProcess = AProcess;
FTable = ATable;
FAccessPath = AAccessPath;
FDirection = ADirection;
FFirstKey = AFirstKey;
FLastKey = ALastKey;
}
private bool IsSubset(Row ARow, TableBufferIndex AIndex)
{
foreach (Schema.Column LColumn in ARow.DataType.Columns)
{
if (!AIndex.KeyRowType.Columns.Contains(LColumn.Name) && !AIndex.DataRowType.Columns.Contains(LColumn.Name))
{
return(false);
}
}
return(true);
}
// TODO: Compile row types for each index, saving column indexes to prevent the need for lookup during insert, update, and delete.
private void InternalInitialize(ServerProcess AProcess)
{
Schema.RowType LKeyRowType;
Schema.RowType LDataRowType;
// Create the indexes required to store data as described by the given table type
// Determine Fanout, Capacity, Clustering Key, KeyLength, DataLength
FClusteringKey = TableVar.FindClusteringOrder(AProcess.Plan);
//Schema.Key LClusteringKey = TableVar.FindClusteringKey();
//FClusteringKey = new Schema.Order(LClusteringKey, AProcess.Plan);
LKeyRowType = new Schema.RowType(FClusteringKey.Columns);
LDataRowType = new Schema.RowType();
foreach (Schema.Column LColumn in TableVar.DataType.Columns)
{
if (!FClusteringKey.Columns.Contains(LColumn.Name))
{
LDataRowType.Columns.Add(new Schema.Column(LColumn.Name, LColumn.DataType));
}
}
// Add an internal identifier for uniqueness of keys in nonunique indexes
#if USEINTERNALID
FInternalIDColumn = new Schema.TableVarColumn(new Schema.Column(CInternalIDColumnName, AProcess.Plan.Catalog.DataTypes.SystemGuid), Schema.TableVarColumnType.InternalID);
LDataRowType.Columns.Add(FInternalIDColumn.Column);
#endif
// Create the Clustered index
FClusteredIndex =
new TableBufferIndex
(
AProcess,
FClusteringKey,
LKeyRowType,
LDataRowType,
true,
FFanout,
FCapacity
);
Indexes.Add(FClusteredIndex);
// DataLength and DataColumns for all non clustered indexes is the key length and columns of the clustered key
LDataRowType = LKeyRowType;
// Create non clustered indexes for each key and order (unique sets)
Schema.Order LKey;
foreach (Schema.Key LNonClusteredKey in TableVar.Keys)
{
if (!FClusteringKey.Includes(LNonClusteredKey))
{
LKey = new Schema.Order(LNonClusteredKey, AProcess.Plan);
if (!Indexes.Contains(LKey))
{
LKeyRowType = new Schema.RowType(LKey.Columns);
Indexes.Add
(
new TableBufferIndex
(
AProcess,
LKey,
LKeyRowType,
LDataRowType,
false,
FFanout,
FCapacity
)
);
}
}
}
foreach (Schema.Order LOrder in TableVar.Orders)
{
// This is a potentially non-unique index, so add a GUID to ensure uniqueness of the key in the BTree
LKey = new Schema.Order(LOrder);
#if USEINTERNALID
if (!LKey.Includes(LClusteringKey))
{
Schema.OrderColumn LUniqueColumn = new Schema.OrderColumn(FInternalIDColumn, true);
LUniqueColumn.Sort = ((Schema.ScalarType)LUniqueColumn.Column.DataType).GetUniqueSort(AProcess.Plan);
LKey.Columns.Add(LUniqueColumn);
}
#endif
if (!Indexes.Contains(LKey))
{
LKeyRowType = new Schema.RowType(LKey.Columns);
Indexes.Add
(
new TableBufferIndex
(
AProcess,
LKey,
LKeyRowType,
LDataRowType,
false,
FFanout,
FCapacity
)
);
}
}
}
