Database management method, program thereof and database management apparatus

A database management method in a computer for retrieving structured data by using an index concerning at least one structured data, the method comprising the steps of:

• accepting input of the structured data and storing the structured data in a storage;
• conducting structure analysis of the input structured data, and generating structure analysis information containing names of structure elements included in the structured data, relations among the structure elements, and appearance locations, in the structured data, of the structure elements;
• continuing processing of reflecting the generated structure analysis information to the index until a predetermined time elapses;
• registering a data identifier of structured data that is not reflected to the index and pointer information for accessing structure analysis information generated on the basis of the structured data, as unreflected data management information in the storage;
• and
• when an input of a retrieval request of the structured data containing a structure condition of the structured data is accepted and structured data that is an object of the retrieval request is structured data that is not reflected to the index,
• referring to the unreflected data management information, reading out structured data that is not reflected to the index and structure analysis information generated on the basis of the structured data from the storage, and
• referring to the structure analysis information thus read out, discriminating an appearance location, in the structured data, of a structure element satisfying the structure condition, and retrieving data satisfying the retrieval request from data in the discriminated appearance location included in the structured data read out.

A database management apparatus for retrieving structured data by using an index concerning at least one structured data, the database management apparatus comprising:

• an input processing part for accepting input of the structured data and storing the structured data in a storage;
• an index registration processing part for conducting structure analysis of the input structured data, generating structure analysis information containing names of structure elements included in the structured data, relations among the structure elements, and appearance locations, in the structured data, of the structure elements, calculating a processing cost required to reflect the input structured data to the index on the basis of the generated structure analysis information, making a decision whether the calculated processing cost exceeds a predetermined threshold, reflecting the structured data to the index when the calculated processing cost does not exceed the predetermined threshold, preventing reflecting the structured data to the index when the calculated processing cost exceeds the predetermined threshold;
• a structure analysis information management part for registering a data identifier of structured data that is not reflected to the index and pointer information for accessing structure analysis information generated on the basis of the structured data, as unreflected data management information in the storage;
• and
• an index retrieval processing part responsive to an input of a retrieval request of the structured data containing a structure condition of the structured data being accepted and structured data that is an object of the retrieval request being structured data that is not reflected to the index, for referring to the unreflected data management information, reading out structured data that is not reflected to the index and structure analysis information generated on the basis of the structured data from the storage, retrieving structure analysis information satisfying the structure condition from the structure analysis information read out, discriminating an appearance location, in the structured data, of a structure element indicated in the structure condition from the retrieved structure analysis information, and retrieving data satisfying the retrieval request from data in the discriminated appearance location.