Mike Yearwood
Toronto, Ontario, Canada
Information générale
Catégorie:
Base de données, Tables, Vues, Index et syntaxe SQL
Versions des environnements
Network:
Windows 2008 Server
>>Hi all
>>
>>Here's an interesting problem I found in an application I inherited.
>>
>>I strongly advise against single letter aliases in SQL and in VFP from the perspective of readability and maintainability. Be especially careful with M as an alias in VFP SQL.
>>
>>create table tmpinvoices free (field1 c(10))
>>local ltDatetime
>>ltDatetime = datetime()
>>select m.field1,m.ltDatetime as tdatetime from tmpinvoices m into cursor c_Result
>>
>>You will get an error that column ltDatetime is not found. OK. So drop the m. from ltDatetime, but now you are slowing your query - admittedly very little, but I don't like doing things half-fast. ;)
>>
>>I tried to add this to the mdot topic on the wiki, but my changes are not being saved.
>
>Single letter aliases are OK.
How can you say that?
Using index tag Deleted to rushmore optimize intermediate result
Rushmore optimization level for intermediate result: full
Using index tag Recddate to rushmore optimize table d
Using index tag Deleted to rushmore optimize table d
Rushmore optimization level for table d: full
Using index tag Deleted to rushmore optimize table e
Rushmore optimization level for table e: full
Using index tag Deleted to rushmore optimize table f
Rushmore optimization level for table f: full
Joining intermediate result and table d using index tag Batchid
Joining intermediate result and table e using index tag Id
Joining intermediate result and table f using index tag Ccode
What is table E? I don't know either. Ya. Very maintainable.
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