public DataRow GetEmptyDataRow(string tableName)
{
// Get table
var table = db.Dmvs.Objects
.Where(x => x.Name == tableName && (x.Type == ObjectType.USER_TABLE || x.Type == ObjectType.SYSTEM_TABLE))
.SingleOrDefault();
if (table == null)
throw new UnknownTableException(tableName);
// Get index
var clusteredIndex = db.Dmvs.Indexes
.Where(i => i.ObjectID == table.ObjectID && i.IndexID == 1)
.SingleOrDefault();
// Get columns
var syscols = db.Dmvs.Columns
.Where(x => x.ObjectID == table.ObjectID);
// Create table and add columns
var columnsList = new List<DataColumn>();
// If it's a non unique clustered index, add uniquifier column
if (clusteredIndex != null && !clusteredIndex.IsUnique)
columnsList.Add(DataColumn.Uniquifier);
foreach(var col in syscols)
{
var sqlType = db.Dmvs.Types.Where(x => x.SystemTypeID == col.SystemTypeID && x.UserTypeID == x.SystemTypeID).Single();
DataColumn dc;
switch((SystemType)sqlType.SystemTypeID)
{
case SystemType.Decimal:
dc = new DataColumn(col.Name, sqlType.Name + "(" + col.Precision + "," + col.Scale + ")");
break;
default:
dc = new DataColumn(col.Name, sqlType.Name + "(" + col.MaxLength + ")");
break;
}
dc.IsNullable = sqlType.IsNullable;
dc.IsSparse = col.IsSparse;
dc.ColumnID = col.ColumnID;
columnsList.Add(dc);
}
return new DataRow(columnsList);
}
public static ISqlType Create(DataColumn column, RecordReadState readState, CompressionContext compression)
{
switch(column.Type)
{
case ColumnType.Binary:
return new SqlBinary((short)column.VariableFixedLength, compression);
case ColumnType.BigInt:
return new SqlBigInt(compression);
case ColumnType.Bit:
return new SqlBit(readState, compression);
case ColumnType.Char:
return new SqlChar((short)column.VariableFixedLength, compression);
case ColumnType.DateTime:
return new SqlDateTime(compression);
case ColumnType.Decimal:
return new SqlDecimal(column.Precision, column.Scale, compression);
case ColumnType.Image:
return new SqlImage(compression);
case ColumnType.Int:
return new SqlInt(compression);
case ColumnType.Money:
return new SqlMoney(compression);
case ColumnType.NChar:
return new SqlNChar((short)column.VariableFixedLength, compression);
case ColumnType.NText:
return new SqlNText(compression);
case ColumnType.NVarchar:
return new SqlNVarchar(compression);
case ColumnType.RID:
return new SqlRID(compression);
case ColumnType.SmallDatetime:
return new SqlSmallDateTime(compression);
case ColumnType.SmallInt:
return new SqlSmallInt(compression);
case ColumnType.SmallMoney:
return new SqlSmallMoney(compression);
case ColumnType.Text:
return new SqlText(compression);
case ColumnType.TinyInt:
return new SqlTinyInt(compression);
case ColumnType.UniqueIdentifier:
return new SqlUniqueIdentifier(compression);
case ColumnType.Uniquifier:
return new SqlUniquifier(compression);
case ColumnType.VarBinary:
return new SqlVarBinary(compression);
case ColumnType.Varchar:
return new SqlVarchar(compression);
case ColumnType.Variant:
return new SqlVariant(compression);
}
throw new ArgumentException("Unsupported type: " + column);
}
public DataRow GetEmptyIndexRow(string tableName, string indexName)
{
// Get table
var table = db.Dmvs.Objects
.Where(x => x.Name == tableName && (x.Type == ObjectType.USER_TABLE || x.Type == ObjectType.SYSTEM_TABLE))
.SingleOrDefault();
if (table == null)
throw new UnknownTableException(tableName);
// Get index
var index = db.Dmvs.Indexes
.Where(i => i.ObjectID == table.ObjectID && i.Name == indexName)
.SingleOrDefault();
if (index == null)
throw new UnknownIndexException(tableName, indexName);
if (index.IndexID == 0)
throw new ArgumentException("Can't create DataRow for heaps.");
// Determine if table is clustered or a heap. If we're not scanning the clustered index itself, see if
// table has a clustered index. If not, it's a heap.
bool isHeap = true;
if (index.IndexID == 1 || db.Dmvs.Indexes.Any(i => i.ObjectID == table.ObjectID && i.IndexID == 1))
isHeap = false;
// Get index columns
var idxColumns = db.Dmvs.IndexColumns
.Join(db.Dmvs.Columns, ic => new { ic.ColumnID, ic.ObjectID }, c => new { c.ColumnID, c.ObjectID }, (ic, c) => new { ic.ObjectID, ic.IndexID, ic.KeyOrdinal, c.IsNullable, ic.IsIncludedColumn, c.SystemTypeID, c.Name, c.MaxLength })
.Where(x => x.ObjectID == table.ObjectID && x.IndexID == index.IndexID)
.OrderBy(x => x.KeyOrdinal);
// Get first index partition
var idxFirstPartition = db.Dmvs.SystemInternalsPartitions
.Where(p => p.ObjectID == table.ObjectID && p.IndexID == index.IndexID)
.OrderBy(p => p.PartitionNumber)
.First();
if (idxColumns.Count() == 0)
throw new Exception("No columns found for index '" + indexName + "'");
// Get rowset columns - these are the ones implicitly included in the index
var partitionColumns = db.Dmvs.SystemInternalsPartitionColumns
.Where(pc => pc.PartitionID == idxFirstPartition.PartitionID && pc.KeyOrdinal > idxColumns.Max(ic => ic.KeyOrdinal))
.OrderBy(pc => pc.KeyOrdinal);
// Add columns as specified in sysiscols
var columnsList = new List<DataColumn>();
foreach(var col in idxColumns)
{
var sqlType = db.Dmvs.Types.Where(x => x.SystemTypeID == col.SystemTypeID).Single();
// TODO: Handle decimal/other data types that needs more than a length specification
var dc = new DataColumn(col.Name, sqlType.Name + "(" + col.MaxLength + ")");
dc.IsNullable = col.IsNullable;
dc.IsIncluded = col.IsIncludedColumn;
columnsList.Add(dc);
}
// Add remaining columns as specified in sysrscols
foreach (var col in partitionColumns)
{
var sqlType = db.Dmvs.Types.Where(x => x.UserTypeID == col.SystemTypeID).Single();
// The uniquifier for clustered tables needs special treatment. Uniquifier is detected by the system type and
// the fact that it's stored in the variable length section of the record (LeafOffset < 0).
if (!isHeap && col.SystemTypeID == (int)SystemType.Int && col.LeafOffset < 0)
{
columnsList.Add(DataColumn.Uniquifier);
continue;
}
// The RID for heaps needs special treatment. RID is detected by system type (binary(8)) and by
// being the last column in the record.
if (isHeap && col.SystemTypeID == (int)SystemType.Binary && col.MaxLength == 8 && col.KeyOrdinal == partitionColumns.Max(pc => pc.KeyOrdinal))
{
columnsList.Add(DataColumn.RID);
continue;
}
// We don't have the corresponding column name from the clustered key (though it could be queried).
// Thus we'll just give them an internal name for now.
var dc = new DataColumn("__rscol_" + col.KeyOrdinal, sqlType.Name + "(" + col.MaxLength + ")");
dc.IsNullable = col.IsNullable;
// Clustered index columns that are not explicitly included in the nonclustered index will be
// implicitly included.
dc.IsIncluded = true;
columnsList.Add(dc);
}
return new DataRow(columnsList);
}
