Plateforme Level Extreme
Abonnement
Profil corporatif
Produits & Services
Support
Légal
English
Had to tell client to go with Delphi 2
Message
 
À
23/05/1997 08:26:30
Information générale
Forum:
Visual FoxPro
Catégorie:
Autre
Divers
Thread ID:
00031289
Message ID:
00033605
Vues:
68
>Hi Asif...thanks for your answer..
>What are compressed character surrogate keys?

Surrogate keys are Primary keys with no underlying meaning. They are especially usefull if you plan to use record-recycling in your database design. This means that you will never have to pack a table, the table will most often reach a terminal size, and the table will not require any periodic maintenance schemes.

>what are tables related via surrogate key?

They are child tables with the surrogate key identifying records which have a relation to one record in the parent table. Whenever, a record in the parent table is marked for deletion, the child tables are also marked for deletion. When a new record has to be added, a Stored Procedure will first try to recycle a record marked for deletion without over-writing the surrogate key in the parent table. The surrogate key(s) in the child tables may be over-written as required.

Keep in mind, that you may still need Primary or Candidate keys in your parent table which do have meaning.

>I am new at writing programs for networks. I need to know how
>to use data from a network drive in a way that gets the best performance.
>Can you suggest ways I can learn? I thought VIEWS would be fast, since they
>work in memory. thanks --rob

To access data over a network, store the data path either in the PATH statement or in a table. If you choose to do the latter, then everytime you use a table, you must build a string on the fly with the path preceeding the table name. For example, if the CUSTOMERS table was on drive H:\123\DATA, you would call something like USE 'H:\123\DATA\customers' IN 0 SHARED

The best way to learn is to experiment.
Précédent
Suivant
Répondre
Fil
Voir

Click here to load this message in the networking platform