public DataProviderTableAccessor(TableType tableType)
: base()
{
TableType = tableType;
_providerInvariantName = TableType.DataSource.ProviderInvariantName;
_connectionString = TableType.DataSource.ConnectionString;
}
public TableType GetTableType(String prefix, String[] identifierPart, bool lookupCache)
{
TableTypeItem tti;
string qualifiedName = MakeQualifiedName(identifierPart);
string key = String.Format("{0}!{1}", prefix, qualifiedName);
lock (_catalogCache)
{
if (lookupCache && _catalogCache.TryGetValue(key, out tti) && tti.IsActual())
return tti.GetTableType();
DataSourceInfo dsi = ResolveTable(prefix, identifierPart);
if (dsi == null)
throw new ESQLException(Properties.Resources.UnknownDataSource, qualifiedName);
TableType tableType;
switch (dsi.TableAccessor)
{
case AcessorType.DataProvider:
tableType = GetDataProviderTableType(dsi, GetProviderTableName(dsi, identifierPart));
break;
case AcessorType.XMLFile:
{
string fullPath = GetFilePath(qualifiedName, "xml");
tableType = new TableType(qualifiedName, fullPath, dsi, null);
}
break;
case AcessorType.DataTable:
{
string fullPath = GetFilePath(qualifiedName, "xml");
tableType = new TableType(qualifiedName, fullPath, dsi, null);
}
break;
case AcessorType.FlatFile:
{
string fullPath = GetFilePath(qualifiedName, "txt");
tableType = new TableType(qualifiedName, fullPath, dsi, null);
}
break;
default:
throw new NotImplementedException();
}
if (tableType == null)
throw new ESQLException(Properties.Resources.TableDoesNotExists, qualifiedName);
if (dsi.TableAccessor == AcessorType.DataProvider && lookupCache)
_catalogCache.Add(key, new TableTypeItem(tableType));
return tableType;
}
}
public TableTypeItem(TableType tableType)
{
CachedType = tableType;
CreateTimestamp = Stopwatch.GetTimestamp();
}
public DataProviderHelper(TableType tableType)
: this(tableType.DataSource.ProviderInvariantName, tableType.DataSource.ConnectionString)
{
}
public void SetFieldsFromTableType(TableType tableType)
{
FieldNames.Clear();
foreach (RowType.TypeInfo ti in tableType.TableRowType.Fields)
FieldNames.Add(ti.ProviderColumnName);
}
public int GetTableEstimate(TableType tableType, int threshold)
{
TableEstimate tableEstimate;
lock (estimate)
if (!estimate.TryGetValue(tableType, out tableEstimate))
{
tableEstimate = new TableEstimate();
estimate.Add(tableType, tableEstimate);
}
lock (tableEstimate)
{
if (tableEstimate.count == tableEstimate.threshold || tableEstimate.threshold < threshold)
{
DataProviderHelper helper = new DataProviderHelper(tableType);
DbConnection connection = DataProviderHelper.CreateDbConnection(tableType.DataSource.ProviderInvariantName);
connection.ConnectionString = tableType.DataSource.ConnectionString;
connection.Open();
try
{
DbCommand command = connection.CreateCommand();
command.CommandText = helper.GetEstimateRowCountQuery(tableType.ToString(helper), threshold);
tableEstimate.count = Convert.ToInt32(command.ExecuteScalar());
tableEstimate.threshold = threshold;
}
finally
{
connection.Close();
}
}
return tableEstimate.count;
}
}
