| 摘要 |
<p>A real-time database provides the predictable, high speed data access required for on-line applications, while providing flexible searching capabilities. The data retrieval routines include the option to "read-through-lock" to access data in locked data tables, the capability to directly access to data using tuple identifiers, and the capability to directly access unformatted data from input areas which contain blocks of unformatted data. The data updating routines include an option to omit index updating when updating data and an option to update data in a locked data table. Multiple indexes can be defined for a data table. Thus, high speed searches can be performed based on a variety of data fields. The data storage and retrieval mechanisms are independent and there are hash index tables that connect the multiple index keys to the data tables. The data table structure includes a column defined for storing tuple identifier strings. These tuple identifiers can be used as pointers for chaining to related data stored in other data tables. The database has relatively small programmatic memory. There is a common structure for user data tables, index tables and system tables. The database includes a minimum number of routines with certain routines providing multiple functionality.</p> |
