Abstract: A node search method, comprising: setting a current time value as a traversing time value; searching descendent nodes to perform a traversing from a root node to a leaf node according to a tree index data structure; determining whether a preset traversing condition is satisfied by comparing an update time value, which indicates a time when a change to a searched descendent node is made, with the traversing time value; depending on whether the traversing proceeding condition is satisfied, re-performing a traversing from a parent node or continuing traversing to the searched descendent node; and terminating the traversing at a leaf node where no descendent node exists.

Abstract: A PSM complier optimizer analyzes a pattern of the PSM program to generate instruction codes, which will be subjected to a bulk operation and makes the instruction codes for the bulk operation in a form of an array of bind parameters to perform a bulk cursor. Accordingly, the bulk DML processing improves the performance of the PSM program.

Abstract: A PSM complier optimizer analyzes a pattern of the PSM program to generate instruction codes, which will be subjected to a bulk operation and makes the instruction codes for the bulk operation in a form of an array of bind parameters to perform a bulk cursor. Accordingly, the bulk DML processing improves the performance of the PSM program.

Abstract: A data compression apparatus generates a global symbol table for an overlapping data using a part of the entire data to be compressed and a local symbol table that is not overlapped with the global symbol table and compressing data with a block as a unit. The apparatus increase compression efficiency.

Abstract: A distributed system includes a plurality of nodes; and replicas of the nodes. Each of the nodes transmits a commit log of a transaction to its own replica and receives a reply to the commit log from its own replica to complete a local transaction. In the distributed system, one of the nodes to which a transaction is requested transmits a commit message requesting the commit of the transaction to the remaining nodes. Each of the remaining nodes then performs the commit of the transaction based on the commit message to complete a global transaction.

Abstract: A transaction resuming method includes receiving a transaction unit divided into subsets by the unit when performing a transaction with a client, performing a rollback in a reverse order of the transaction when there is an error, and generating a resumable point to resume the transaction. The method further includes providing the resumable point to the client and receiving transaction unit after the resumable point to resume the transaction.

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: An apparatus performs a data migration from a database of a mainframe system to a rehosting solution database of an open system. An unload data set conversion module converts an unload data set, unloaded from the database of the mainframe system, into load files having standard format. A schema information generation module generates a schema information file having conversion rules by segment and field necessary for code system conversion of segment data in the load files having standard format. A code system conversion module converts the load files into load files having a code system of the open system pursuant to the schema information file, wherein the load files. A data load module sequentially reads segment data in the code-converted load files to load the segment data into the rehosting solution database.