Multiplying two fields in a form from different tables

[A Abbas]

Hi,

I am new to access and dont know VB also. I will be really grateful if someone can help me on this.
I have two tables 'LabIssue' and 'Store'.
I created a form for 'LabIssue' in which data will be entered. In the form I want to calculate the 'ChemicalAmount' by multiplying 'Store.Costperunit' with the 'QuantityIssued' which will be entered by the user. ChemicalAmount and QuantityIssued will be stored in 'LabIssue' table. I tried it through the expression builder but im getting #Name? error, did alot of things but couldnt figured out whats the problem.


I am attaching the initial database also for reference. please help me, its really urgent.

[June7]

The #NAME error means Access can't find a reference. The table Store is not included in the form's RecordSource, therefore the field CostPerUnit is not available for the calculation.

The Relationships setup doesn't make sense. The purpose of table Relationships is to associate primary and foreign key fields. The data in the joined fields must be the same. This is how tables are related. You have included CheAmount in a join to CostPerUnit but on the form CheAmount is a calcuation that uses CostPerUnit. Since the two fields cannot be the same, this join is meaningless. Recommend you set the Autonumber field in Store as primary and add a field in LabIssue to save this value as foreign key and set Relationships to reflect that, if I correctly understand these tables' relationship.

Also, calculated results do not save to table without code and there should be no reason to save CheAmount. Perform this calculation as needed.