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Communicator 3000 MPE/iX Release 6.0 (Platform Software Release C.60.00): HP 3000 MPE/iX Computer Systems > Chapter 10 Technical Articles QUERY/iX Enhancements |
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by James Overman SSG Group R&D The following topics in this article review the new enhancements for QUERY/iX and some limitations on their use:
The latest B-Tree enhancement to TurboImage/XL has required some enhancements to the QUERY product to utilize the new features. With the HP32216D.03.11 and N.03.11 releases of QUERY, the new B-Tree access capabilities will be supported within QUERY on systems with the B-Tree software release. QUERY is fully backward compatible with the prior releases of TurboIMAGE/XL and QUERY. New messages will be seen when B-trees are utilized by a database and the FORM command is entered. The number of indexed sets, the wildcard character, the status of the BTREEMODE1 flag when OFF, and the individual sets and items that have been indexed will be reported as shown in the following example: Figure 10-1 FORM Example
The last line above shows another enhancement to QUERY that reflects the Dynamic Dataset Capacity Expansion capability. When a dataset has utilized the Dynamic Expansion feature, QUERY will display the CURRENT, MAXIMUM, and INITIAL capacities and the INCREMENT amount. The FORM SETS output has been slightly modified such that the heading reflects that the Current capacity is being reported rather than the Maximum capacity. QUERY will automatically invoke the B-Tree retrieval feature for the FIND, LIST, SUBSET, and MULTIFIND commands when a wildcard character is used in the search value. As QUERY may have up to ten databases open and each could have a different wildcard, the wildcard for the DEFINED database will be used when specified, else the first wildcard specified by an open database will be used. QUERY uses modes 21 or 24 for B-Tree DBFIND for best performance. Certain possible wildcard characters are used by QUERY for syntax scanning and are limited in their usage. These special characters may be utilized when the data values are delimited by double quotes (for example, tilde, carat, comma, and parenthesis). Figure 10-2 Title not available (Wildcard Character Limitations )
QUERY will utilize the B-Tree functionality when possible for both character and binary data types. The wildcard feature is only implemented by TurboIMAGE/XL for character data types (X and U) and not for binary data types. Neither has the Not Equal operator been implemented for B-trees and so QUERY will continue to use the older access methods (normally serial reads) for Not Equal retrievals. Note that the LIST command always uses a serial read but will apply the wildcard search character for relations. When a database has the BTREEMODE1 flag set to OFF, QUERY will not attempt to use the B-Tree functionality for Wildcard retrievals. This condition is reported by all forms of the FORM command. The FIND, MULTIFIND, and SUBSET commands have been enhanced to accept a NO MATCH alternative such that all data records NOT MATCHING the pattern provided are returned by the commands. The new form of the FIND command is:
The MULTIFIND and SUBSET command syntax are similarly enhanced. The NO may be followed by additional characters such that all of the following examples are accepted:
This NO Matching enhancement is NOT related to the B-Tree functionality and does not utilize the B-Tree retrieval mechanisms. |
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