Format conversion of storage data using an efficient division of data

A database apparatus that writes out pieces of data in computable format on a main memory device and in storage format on a secondary memory device, the database apparatus comprising:

• secondary memory means for storing pieces of data, each of which includes a plurality of elements as data in storage format;
• main memory means for storing pieces of data, each of which includes a plurality of elements as data in computable format, and for storing validity of the pieces of data, the validity indicating consistency between elements in each of the pieces of data stored in the main memory means and elements in a corresponding piece of data stored in the secondary memory means;
• a main memory manager that performs a check as to whether one of the pieces of data stored in the secondary memory means has been updated, and updates the validity of the pieces of data stored in the main memory means in accordance with the check;
• first determination means for determining whether one of the pieces of data stored in the main memory means contains at least one element that is consistent with the corresponding element in the secondary memory means based on the validity of the pieces of data stored in the main memory means;
• second determination means for determining a valid element in a piece of data which is consistent with the corresponding element in the secondary memory means, the first determination means determining that at least one element of that piece of data is consistent with the corresponding element in the secondary memory means;
• and
• storage means for converting the element in computable format that corresponds to the element that the second determination means has determined to be valid into storage format, and for storing the element from the main memory means in the secondary memory means.

A database apparatus that reads pieces of data in storage format on a secondary memory device as pieces of data in computable format on a main memory device to process the pieces of data and writes out pieces of data in computable format on the main memory device as pieces of data in storage format on the secondary memory device, the database apparatus comprising:

• secondary memory means for storing pieces of data, each of which includes a plurality of elements as data in storage format;
• main memory means for storing pieces of data, each of which includes a plurality of elements as data in computable format, and for storing validity of the pieces of data, the validity indicating consistency between elements in each of the nieces of data stored in the main memory means and elements in a corresponding piece of data stored in the secondary memory means;
• a main memory manager that performs a check as to whether one of the pieces of data stored in the secondary memory means has been updated, and updates the validity of the pieces of data stored in the main memory means in accordance with the check;
• first determination means for determining whether one of the pieces of data stored in the main memory means contains at least one element that is inconsistent with the corresponding element in the secondary memory means based on the validity of the pieces of data stored in the main memory means;
• second determination means for determining an invalid element and a valid element in a piece of data which are inconsistent and consistent, respectively, with the corresponding element in the secondary memory means, the first determination means determining that at least one element of that piece of data is inconsistent with the corresponding element in the secondary memory means;
• loading means for converting the elements in storage format that correspond to the element that the second determination means has determined to be invalid into computable format and for loading the element into the main memory means the main memory manager updating the validity of the pieces of data stored in the main memory means in accordance with loading of the elements by the loading means;
• and
• storage means for converting the elements in computable format that correspond to the element that the second determination means has determined to be valid into storage format and for storing the element from the main memory means in the secondary memory means.

A database apparatus that mutually converts and uses pieces of data in storage format that are suitable for data storage and pieces of data in computable format for data processing, the apparatus comprising:

• first memory means for storing pieces of data, each of which containing a plurality of elements in computable format;
• second memory means for storing pieces of data, each of which containing a plurality of elements in storage format;
• access request signal receiving means for receiving access requests from the application program for one of the elements of the pieces of data;
• and
• data format conversion means for converting the format of only the element for which an access request has been received between the first memory means and the second memory means when the access request is received for an element by the access request signal receiving means, wherein when the access request is received for the pieces of data, the format of the pieces of data for which the access request has been received is converted between the first memory means and the second memory means.

A database apparatus management method that writes pieces of data that are in storage format in a secondary memory device onto a main memory device as pieces of data in computable format to process the pieces of data, the method comprising the steps of:

• storing validity about the pieces of data, the validity indicating consistency between elements in each of the pieces of data stored in the main memory device and elements in a corresponding piece of data stored in the secondary memory device;
• performing a check as to whether one piece of data stored in the secondary memory device has been updated, and updating the validity of the pieces of data stored in the main memory device in accordance with the check;
• determining whether one of the pieces of data that is stored in the main memory device contains at least one element that is inconsistent with the corresponding element in the secondary memory device based on the validity;
• determining an invalid element in the piece of data which is inconsistent with the corresponding element in the secondary memory device according to the first determination step determining that the piece of data contains an invalid element that is inconsistent with the corresponding element in the secondary memory device;
• converting elements in storage format corresponding to the element that has been determined to be invalid to computable format, and written into the main memory device;
• and
• updating the validity of the pieces of data stored in the main memory device in accordance with conversion of the element.

A database apparatus management method that writes pieces of data that are in storage format in a secondary memory device onto a main memory device as pieces of data in computable format to process the pieces of data, the method comprising the steps of:

• storing validity about the pieces of data, the validity indicating consistency between elements in each of the pieces of data stored in the main memory device and elements in a corresponding piece of data stored in the secondary memory device;
• receiving a loading request for an element in one of the pieces of data;
• performing a check as to whether one niece of data stored in the secondary memory device has been updated, and updating the validity of the pieces of data stored in the main memory device in accordance with the check;
• determining whether one of the pieces of data that is stored in the main memory device and contains the element for which a loading request has been received contains at least one invalid element that is inconsistent with the corresponding element in the secondary memory device based on the validity;
• determining an invalid element in a piece of data which is inconsistent with the corresponding element in the secondary memory device according to the first determination step determining that the piece of data contains an invalid element that is inconsistent with the corresponding element in the secondary memory device;
• converting the corresponding element in storage format to computable format when the element has been determined to be invalid;
• and
• updating the validity of the pieces of data stored in the main memory device in accordance with conversion of the element.

A database apparatus management method that writes pieces of data that are in computable format in a main memory device into a secondary memory device as pieces of data in storage format, the method comprising the steps of:

• storing validity about the pieces of data, the validity indicating consistency between elements in each of the pieces of data stored in the main memory device and elements in a corresponding piece of data stored in the secondary memory device;
• performing a check as to whether one piece of data stored in the secondary memory device has been updated, and updating the validity of the pieces of data stored in the main memory device in accordance with the check;
• determining whether one of the pieces of data that is stored in the main memory device contains at least one element that is consistent with the corresponding element in the secondary memory device based on the validity;
• determining a valid element in the piece of data which is consistent with the corresponding element in the secondary memory device according to the first determination step determining that the piece of data contains a valid element that is consistent with the corresponding element in the secondary memory device;
• and
• converting the element in computable format corresponding to the element that has been determined to be valid to storage format and for storing the element in the secondary memory device.

A database apparatus management method that writes pieces of data that are in computable format in a main memory device into a secondary memory device as pieces of data in storage format, the method comprising the steps of:

• storing validity about the pieces of data, the validity indicating consistency between elements in each of the pieces of data stored in the main memory device and elements in a corresponding piece of data stored in the secondary memory device;
• receiving a storing request for an element in one of the pieces of data;
• performing a check as to whether one piece of data stored in the secondary memory device has been updated, and updating the validity of the pieces of data stored in the main memory device in accordance with the check;
• determining whether one of the pieces of data that is stored in the main memory device and contains the element for which a storing request has been received contains at least one valid element that is consistent with the corresponding element in the secondary memory device based on the validity;
• determining a valid element in a piece of data which is consistent with the corresponding element in the secondary memory device according to the first determination step determining that the piece of data contains a valid element that is consistent with the corresponding element in the secondary memory device;
• and
• converting the corresponding element in computable format to storage format and writing it from the main memory device to the secondary memory device when the element has been determined to be valid.