| 摘要 |
A method and system of providing external transaction protection for a database using the database log or journal. The method involves creating a set of transaction templates which define transactions, using the templates to determine whether each record or entry in the journal represent part of a transaction, and maintaining a set of index file indicating transactions in progress. Each transaction template contains a number of filenames identifying files in the database affected during the transaction defined by the template. Each template also contains a key value representing one or more data fields in the database included in every action performed during the transaction. For each entry in the journal, a determination is made whether the entry belongs to a transaction based on the data fields represented in the entry and the key values associated with the templates. The index files are maintained by creating a new index file for each new transaction, adding data to a given index file from a journal entry which belongs to the transaction associated with the given index file, and deleting index files when transactions with which they are associated are complete. In the event the database is damaged, existing index files are used to determine which transactions did not complete before the database was damaged. The actions which were completed may be rolled back. |
