Abstract: Provided is a method for executing a query in a DBMS. The method may include: receiving a query statement including a pivot operator—the query statement being associated with an original table; executing a pivot operation for the original table in response to reception of the query statement; generating BLOB data by serializing at least a part of an execution result of the pivot operation to a BLOB type; and storing the generated BLOB data in a pivot table.

Abstract: Provided is a method for executing a query in a DBMS. The method may include: receiving a query statement for requesting BLOB data serialized to a binary large object (BLOB) type and stored in a pivot table; determining name information for one or more columns generated as a result of a pivot operation included in respective pivot columns of the pivot table by querying a pivot name table for the pivot table; determining internal storage type information of the pivot table by querying a pivot meta table for the pivot table; and generating output information for the BLOB data corresponding to the query statement based on the determined name information and internal storage type information.

Abstract: A query complier analyzes a query to identify a correlated scalar subquery. The query complier transforms the query having the correlated scalar subquery into a query of AGGREGATION INNER/OUTER JOIN or MAX1ROW INNER/OUTER JOIN depending on a result type of the correlated scalar subquery. The AGGREGATION INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query and AGGREGATE on the joined rows and returns a result of the joined rows of the main query and aggregation value thereof. The MAX1ROW INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query, raises Error when the number of joined rows of the subquery is two or more and returns a result of the row of the main query and the joined row of the subquery.

Abstract: Provided is a method for executing a query in a DBMS. The method may include: receiving a query statement including a pivot operator—the query statement being associated with an original table; executing a pivot operation for the original table in response to reception of the query statement; generating BLOB data by serializing at least a part of an execution result of the pivot operation to a BLOB type; and storing the generated BLOB data in a pivot table.

Abstract: Provided is a method for executing a query in a DBMS. The method may include: receiving a query statement for requesting BLOB data serialized to a binary large object (BLOB) type and stored in a pivot table; determining name information for one or more columns generated as a result of a pivot operation included in respective pivot columns of the pivot table by querying a pivot name table for the pivot table; determining internal storage type information of the pivot table by querying a pivot meta table for the pivot table; and generating output information for the BLOB data corresponding to the query statement based on the determined name information and internal storage type information.

Abstract: A query complier analyzes a query to identify a correlated scalar subquery. The query complier transforms the query having the correlated scalar subquery into a query of AGGREGATION INNER/OUTER JOIN or MAX1ROW INNER/OUTER JOIN depending on a result type of the correlated scalar subquery. The AGGREGATION INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query and AGGREGATE on the joined rows and returns a result of the joined rows of the main query and aggregation value thereof. The MAX1ROW INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query, raises Error when the number of joined rows of the subquery is two or more and returns a result of the row of the main query and the joined row of the subquery.

Abstract: A query complier analyzes a query to identify a correlated scalar subquery. The query complier transforms the query having the correlated scalar subquery into a query of AGGREGATION INNER/OUTER JOIN or MAX1ROW INNER/OUTER JOIN depending on a result type of the correlated scalar subquery. The AGGREGATION INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query and AGGREGATE on the joined rows and returns a result of the joined rows of the main query and aggregation value thereof. The MAX1ROW INNER/OUTER JOIN performs JOIN on the rows of the correlated scalar subquery with the rows of a main query, raises Error when the number of joined rows of the subquery is two or more and returns a result of the row of the main query and the joined row of the subquery.

Abstract: In a multi-level redirection method, a first level redirection of a first request is performed based on static information. At a manager, a second level redirection of a second request is performed to an agent server based on dynamic information. The manager is configured to monitor an individual status of the agent server. The static information is associated with selection of the manager and the dynamic information is associated with selection of the agent server. The second level redirection is application redirection performed based on application protocols and contents used in the first and second request.

Abstract: In a multi-level redirection method, a first level redirection of a first request is performed based on static information. At a manager, a second level redirection of a second request is performed to an agent server based on dynamic information. The manager is configured to monitor an individual status of the agent server. The static information is associated with selection of the manager and the dynamic information is associated with selection of the agent server. The second level redirection is application redirection performed based on application protocols and contents used in the first and second request.