/// <summary>
/// checks if the result for this query is already cached.
/// If not, the result is retrieved from the database.
/// The result is added to the cache, and the result is returned
/// as a ArrayList from the cache.
/// The ArrayList consists of the strings
/// of the first column of the first table in the dataset.
///
/// </summary>
/// <returns>void</returns>
public ArrayList GetStringList(DB.TDataBase db, String sql)
{
ArrayList ReturnValue = new ArrayList();
DataSet ds = GetDataSet(db, sql);
foreach (DataRow row in ds.Tables[0].Rows)
{
ReturnValue.Add(Convert.ToString(row[0]));
}
return(ReturnValue);
}
/// <summary>
/// checks if the result for this query is already cached.
/// If not, the result is retrieved from the database.
/// The result is added to the cache, and the result is returned
/// as a DataSet from the cache.
/// </summary>
/// <param name="db"></param>
/// <param name="sql"></param>
/// <param name="ATable">can already have some prepared columns; optional parameter, can be null
/// </param>
/// <returns>void</returns>
public DataSet GetDataSet(DB.TDataBase db, String sql, DataTable ATable)
{
DB.TDBTransaction ReadTransaction;
Boolean NewTransaction = false;
DataSet newDataSet;
int counter = 0;
foreach (string sqlstr in storedSQLQuery)
{
if (sqlstr == sql)
{
// create a clone of the result, so that the returned datasets
// can be treated separately
return(((DataSet)storedDataSet[counter]).Copy());
}
counter++;
}
try
{
ReadTransaction = DBAccess.GDBAccessObj.GetNewOrExistingTransaction(IsolationLevel.ReadCommitted,
TEnforceIsolationLevel.eilMinimum,
out NewTransaction);
if (ATable == null)
{
newDataSet = db.Select(sql, "Cache", ReadTransaction);
}
else
{
newDataSet = new DataSet();
newDataSet.Tables.Add(ATable);
ATable.TableName = "Cache";
db.Select(newDataSet, sql, "Cache", ReadTransaction);
}
}
finally
{
if (NewTransaction)
{
DBAccess.GDBAccessObj.CommitTransaction();
}
}
storedDataSet.Add(newDataSet);
storedSQLQuery.Add(sql);
// return a copy, so that changes to the dataset don't affect the stored copy.
return(newDataSet.Copy());
}
/// <summary>
/// checks if the result for this query is already cached.
/// If not, the result is retrieved from the database.
/// The result is added to the cache, and the result is returned
/// as a DataTable from the cache.
/// </summary>
/// <param name="db"></param>
/// <param name="sql"></param>
/// <param name="ATable">can already have some prepared columns; optional parameter, can be nil
/// </param>
/// <returns>void</returns>
public DataTable GetDataTable(DB.TDataBase db, String sql, DataTable ATable)
{
return(GetDataSet(db, sql, ATable).Tables["Cache"]);
}
/// <summary>
/// checks if the result for this query is already cached.
/// If not, the result is retrieved from the database.
/// The result is added to the cache, and the result is returned
/// as a DataTable from the cache.
/// </summary>
/// <param name="db"></param>
/// <param name="sql"></param>
/// <returns></returns>
public DataTable GetDataTable(DB.TDataBase db, String sql)
{
return(GetDataTable(db, sql, null));
}
/// <summary>
/// checks if the result for this query is already cached.
/// If not, the result is retrieved from the database.
/// The result is added to the cache, and the result is returned
/// as a DataSet from the cache.
/// </summary>
/// <param name="db"></param>
/// <param name="sql"></param>
/// <returns></returns>
public DataSet GetDataSet(DB.TDataBase db, String sql)
{
return(GetDataSet(db, sql, null));
}