/// <summary>
/// Returns the query for selecting the records,
/// subclasses can override this for custom behaviour.
/// </summary>
protected internal virtual string GetSelectQuery()
{
StringBuilder query = new StringBuilder();
// Default codepath for MySQL, HSQLDB, etc. Relies on LIMIT/OFFSET for splits.
if (dbConf.GetInputQuery() == null)
{
query.Append("SELECT ");
for (int i = 0; i < fieldNames.Length; i++)
{
query.Append(fieldNames[i]);
if (i != fieldNames.Length - 1)
{
query.Append(", ");
}
}
query.Append(" FROM ").Append(tableName);
query.Append(" AS ").Append(tableName);
//in hsqldb this is necessary
if (conditions != null && conditions.Length > 0)
{
query.Append(" WHERE (").Append(conditions).Append(")");
}
string orderBy = dbConf.GetInputOrderBy();
if (orderBy != null && orderBy.Length > 0)
{
query.Append(" ORDER BY ").Append(orderBy);
}
}
else
{
//PREBUILT QUERY
query.Append(dbConf.GetInputQuery());
}
try
{
query.Append(" LIMIT ").Append(split.GetLength());
query.Append(" OFFSET ").Append(split.GetStart());
}
catch (IOException)
{
}
// Ignore, will not throw.
return(query.ToString());
}
/// <summary>Returns the query for selecting the records from an Oracle DB.</summary>
protected internal override string GetSelectQuery()
{
StringBuilder query = new StringBuilder();
DBConfiguration dbConf = GetDBConf();
string conditions = GetConditions();
string tableName = GetTableName();
string[] fieldNames = GetFieldNames();
// Oracle-specific codepath to use rownum instead of LIMIT/OFFSET.
if (dbConf.GetInputQuery() == null)
{
query.Append("SELECT ");
for (int i = 0; i < fieldNames.Length; i++)
{
query.Append(fieldNames[i]);
if (i != fieldNames.Length - 1)
{
query.Append(", ");
}
}
query.Append(" FROM ").Append(tableName);
if (conditions != null && conditions.Length > 0)
{
query.Append(" WHERE ").Append(conditions);
}
string orderBy = dbConf.GetInputOrderBy();
if (orderBy != null && orderBy.Length > 0)
{
query.Append(" ORDER BY ").Append(orderBy);
}
}
else
{
//PREBUILT QUERY
query.Append(dbConf.GetInputQuery());
}
try
{
DBInputFormat.DBInputSplit split = GetSplit();
if (split.GetLength() > 0)
{
string querystring = query.ToString();
query = new StringBuilder();
query.Append("SELECT * FROM (SELECT a.*,ROWNUM dbif_rno FROM ( ");
query.Append(querystring);
query.Append(" ) a WHERE rownum <= ").Append(split.GetEnd());
query.Append(" ) WHERE dbif_rno > ").Append(split.GetStart());
}
}
catch (IOException)
{
}
// ignore, will not throw.
return(query.ToString());
}