When there are multiple choices for keys within a table, CONNX selects the optimal key choice.

There are two ways to manually override the selected key.

• Place {usekey <key no.> } directly after the table name. CONNX will use the specified key, when possible.  However, the usage of the key is not guaranteed.

• CONNX will accept a string that contains all of the key field names, separated by commas, instead of the key number. Place {Usekey '<keycolum#1>[,<keycolum#2>...]'} directly after the table name.

 

 

Example:

Key number

SELECT * FROM equipmnt_rms {usekey 2} where equipmnt_rms.location='MIS DEPT.' and equipmnt_rms.description='TRAILBLAZER MODEM'

 

Key field names

 

The sample PRODUCT table that comes with CONNX has three keys on it:

 

Key #0 = a composite key of orderid, customerid, and productid

Key #1 = customerid

Key #2 = productid

 

When issuing the following SQL statement, CONNX will by default select key #0 as the best key candidate.

SELECT * FROM RMS.dbo.orders_rms

where customerid = 'MERRG'

and productid = 40

and orderid = 1

 

 

 

The following example uses tells CONNX to use the productid key.

 

 

The following example uses tells CONNX to use the orderid, customerid, productid composite key.