dessam@gara.une.oz.au (Daryl Essam STHO) (09/26/90)
I am a member of a group that is currently investigating database integrity. If anyone knows of any databases that have strong integrity checks, could they please mail information about them to me. The sort of minimal information we are interested in is name, producer and if possible, price. Also, if you feel it is not to much trouble, an outline of the databases' features would be appreciated. Thanks in advance Daryl Essam
neal@mnopltd.UUCP (09/27/90)
-> I am a member of a group that is currently investigating
->database integrity. If anyone knows of any databases that have
->strong integrity checks, could they please mail information about them to me.
->The sort of minimal information we are interested in is name, producer and
->if possible, price. Also, if you feel it is not to much trouble, an
->outline of the databases' features would be appreciated.
-> Thanks in advance
-> Daryl Essam
->Organization: University of New England, Armidale, Australia
->
The strongest one I am aware of is Progress, from Progress Software.
Things I would call integrity are:
automatic transaction scoping and backout;
dictionary validations expressions for:
each field;
record deletion;
The runtime distribution for Progress is fairly inexpensive; the development
system is not. You may want to check your local rep:
Progress Language Pty. Ltd.
Melbourne phone: 61/(0)3 823 4451
Sydney phone: 61/(0)2 906 1931
------------------------------------------------------------------------------
Neal Rhodes MNOP Ltd (404)- 972-5430
President Lilburn (atlanta) GA 30247 Fax: 978-4741
emory!mnopltd!neal
------------------------------------------------------------------------------ethan@thinc.UUCP (pri=-5*Ethan A. Lish of THINC) (09/28/90)
In article <124@mnopltd.UUCP>, neal@mnopltd.UUCP writes: > > -> I am a member of a group that is currently investigating > ->database integrity. If anyone knows of any databases that have > ->strong integrity checks, could they please mail information about them to me. > ->The sort of minimal information we are interested in is name, producer and > ->if possible, price. Also, if you feel it is not to much trouble, an > ->outline of the databases' features would be appreciated. > -> Thanks in advance > -> Daryl Essam > ->Organization: University of New England, Armidale, Australia > -> > > The strongest one I am aware of is Progress, from Progress Software. > Concurrency Control: Automatic concurrency control with full transaction support ensures that no users sees an inconsistent view of the database, and that no database updates are lost. This is accomplished without complex record locking protocols, yet the user can easily control transaction size and the types of locks to any level. Records may be accessed with exclusive, shared or no locks. Transaction leveling is the key to the "two-phase" commit feature. Automatic Crash Recovery: The PROGRESS(tm) RDBMS maintains a "before-image" file that holds unmodified copies of all updated records. In the event of transaction conflicts or system failure, this "before-image" file is used to automatically back out all incomplete transactions, assuring database intergrity. If as a result of a partially completed transaction, data has been written to disk, PROGRESS(tm) restores those records and all affected indexes to their "pre-transaction" condition. This is known as "Roll-Back" Recovery. Roll-Forward Recovery: Roll-Forward recovery provides an additional way to protect against hardware failures. A log file on a seperate disk is used to maintain an after image of all transactions completed since the last backup. In the event the disk hosting the database is lost, the database would be restored from tape. Then subsequent transactions are rolled into the database, restoring the database to its state at the time of hardware failure. **** For more information on these or other PROGRESS(tm) Features *** You may call/write/email you questions to the address below. **** Let me show you how PROGRESS(tm) can solve your application issues *** Thank you, Ethan -- "Life's an adventure.. go for it." Ethan A. Lish ---- 301.652.0651 ---- {uunet}!thinc!ethan Tomorrow's Horizons, Inc.,4807 Bethesda Ave, #330, Bethesda, MD 20814