Advise on queries

[rainbows]

i would like to know which way i should take this as i have seen both ways in a form

should i just uses the " star " in the query or select the fields i want if a am using the query to create a form

thanks
steve

 

[ebs17]

It is good style to use only the fields that are really needed. So these fields are to be listed by name and therefore individually.

Why?
For fields that are called, the contents must also be loaded. Loading unnecessary data costs time, puts additional load on the network, etc.
If the table contains such clumsiness as lookup fields or calculated fields, they would also perform their recalculations, even if they are not needed.

//OT:
Why do you always upload such large images with quite little meaningfulness?
For example, when talking about a query, the SQL statement from the SQL view, presented as code text, shows much more. Moreover, you could immediately copy, correct and return the suggestion.

 

[The_Doc_Man]

@rainbows - concur with ebs17. Specifying only the fields you want means less network traffic, and besides that, more data can be fit into the I/O buffers that are behind the scenes during the data transfers. This increases memory usage efficiency. The "*" calls back everything in the table or query and thus calls for "wider" records than a selective query would call back. For slower networks, "more data" isn't always your friend.

 

[rainbows]

thank you , to take that further if you have a table with say 20 fields in it and a form with 20 fields in it and then you want to create another form using data from that table say 7 fields is it best to call up that table again as i have to get the 7 fields or would you create a form with a query that just calls up them 7 fields

steve

 

[ebs17]

or would you create a form with a query that just calls up them 7 fields

Exactly that.
Also remember that you work in a form as well. Filters, Requery ... all this leads to the retrieval of data from the table.

To make it noticeable: It is for sure a difference for you if you carry 7 bottles of water or 20 bottles of water, even more if you are busy for a longer time and have to walk long ways over hill and dale.
Your computer and your programs are also only water carriers and thank you if you are careful with the allocation of work.

 

[rainbows]

on the form below i used a table with the "*" and the drop down box " find batch number works ok , i have now tried to use the query without the "*" and the drop down box did not work i have tried to add another one drop down box and you can see i only get 2 option . if i change it back to the table and use the " *" it works again . and idea why ?

thanks steve

 

[ebs17]

Ideas I have.
If the wizard offers only all fields by * instead of single selection on fields, the wizard is not suitable or you use it wrong.

I myself don't use this wizard practically at all, but I set the properties of the combo box in the property sheet by hand.

In all cases you should open your eyes and know what you are doing.