Ledger Database Journal Queries for Deleted Document History
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Solution Overview
Problem
Conventional database management systems, both relational and non-relational, face limitations in providing a comprehensive history of changes to documents, especially when documents are deleted, and lack efficient mechanisms for querying transaction histories.
Innovation Solution
A ledger-based database management system that utilizes journal and summary data structures to record and query immutable transaction histories, allowing clients to access and retrieve changes to documents through journal queries processed by a query processor, transaction coordinator, and storage system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If conventional database management systems store and retrieve data using traditional relational or non-relational models, then data storage and retrieval operations can be performed, but the systems cannot provide comprehensive history of changes to documents including deleted documents
Solution Approach 1:
The patent segments the database into two distinct components: a journal that stores immutable transaction histories and a summary that stores current document states. This segmentation allows the journal to preserve complete change histories including deleted documents while the summary provides efficient current state access, resolving the contradiction between information preservation and structural complexity.
Solution Approach 2:
The patent introduces a journal as an intermediary component between data writing operations and data retrieval operations. The journal acts as a mediator that captures all transactions immutably, allowing historical queries to be performed without affecting the current state storage, thus preserving complete change histories while managing complexity through a dedicated intermediary structure.
2Productivity
If conventional database systems use fixed-length records and structured query language, then efficient data retrieval can be achieved, but the systems lack mechanisms to query transaction histories effectively
Solution Approach 1:
The patent makes the journal table schema derived from and compatible with the document table schema, allowing the same query language and mechanisms to be used for both current document data and historical transaction data. This universal schema approach enables efficient data retrieval for both current and historical data while providing versatile querying capabilities across different data types.
Solution Approach 2:
The patent implements a dynamic schema derivation mechanism where the journal table schema is automatically derived from the document table schema. This dynamic adaptation allows the system to maintain efficient query structures while adapting to different data types and query requirements, providing both retrieval efficiency and query flexibility.
3Quantity of substance
If conventional databases delete documents to free up space, then storage efficiency is improved, but the complete history of changes including deleted documents cannot be accessed
Solution Approach 1:
The patent extracts the historical record function from the main document storage by moving all transaction histories into a separate journal. This extraction allows documents to be deleted from the main storage to free up space while their transaction histories are preserved in the journal, resolving the contradiction between storage efficiency and information preservation.
Solution Approach 2:
The patent creates a copy of the transaction history in the journal that is separate from the original document storage. This copying mechanism allows the original documents to be deleted for space efficiency while preserved copies of the transaction data remain in the journal, enabling access to complete change histories without compromising storage utilization.
4Ease of operation
If conventional database systems use rigid structured query language, then standardized data access is achieved, but the systems cannot support loosely structured data effectively
Solution Approach 1:
The patent changes the schema parameters by deriving the journal table schema dynamically from the document table schema rather than using fixed rigid structures. This parameter change allows the system to maintain standardized query access while adapting to loosely structured data, as the schema derivation process can accommodate varying data structures while preserving ease of operation through consistent query mechanisms.
Data Source
AI summary
A database management system stores data for a table as a journal of transaction. The records of the journal comprise information indicative of changes applied to a document of the table. The database receives a query on a table of transactions performed on the table. In response to the query on the table of transactions, the database generates results by retrieving and projecting the records of the journal in accordance with the query. The results of the query are indicative of changes applied to the document of the table.