MS Access query with parameter from combobox in form does not return any results - vba

Question

I have created an MS Access database with several tables and queries but the problem described further down is about the following:
tEmployee table contains employee data as the name implies.
tCases table contains data about court cases.
Each case can be assigned to only one employee. I have created a relationship from [tCases]![assignedTo] field to tEmployee.
fSearches is a form to perform searches among the cases. It includes a combobox cEmployee which is populated from [tEmployee].[surname] and a command button to perform the search.
GOAL: to select employee in [fSearches]![cEmployee], hit the button and show all the cases assigned to this employee in another form named fResultsCases.
This is the code for the button where lines in comments are some of the things I've tried:
If cEmploee.ListIndex = -1 Then
MsgBox "You have to select employee to perform search.", title:="Missing value!"
Else
tHidden2.SetFocus
tHidden2.Text = "assigned to " & cEmploee & "."
DoCmd.OpenForm "fResultsCases"
'Forms("fResultsCases").RecordSource = "SELECT * FROM tCases WHERE [tCases]![assignedTo] like [Forms]![fSearches]![cEmploee];"
'Forms("fResultsCases").RecordSource = "SELECT * FROM tCases WHERE tCases .[assignedTo] = [Forms]![fSearches]![cEmploee];"
Forms("fResultsCases").RecordSource = "SELECT * FROM tCases WHERE [assignedTo] = [Forms]![fSearches]![cEmploee];"
Forms("fResultsCases").Recalc
End If
With all the above mentioned I get the following:
[fResultsCases] opens but does not return any case.
I tried to omit the WHERE clause and [fResultsCases] returns all cases as expected.
Then I tried to narrow things down to understand the problem by creating a simple query with one parameter and got exactly the same results.
SELECT tCases.[case number], tCases.subject, tCases.fromDt, tCases.toDt,
tCases.assignedTo, tCases.[date assigned], tCases.[date completed]
FROM tCases
WHERE (((tCases.assignedTo)=[Forms]![fSearches]![cEmploee]));
It seems like I'm missing something about the WHERE clause when it comes to combobox values but I can't figure it out. I am new to MS Access. Any help will be very appreciated.
UPDATE:
cEmploee rowsource property: SELECT [tEmployee].surname FROM tEmployee ORDER BY [surname];
cEmploee bound column property: 1

Answer 1

I cannot recreate your issue replicating your setup with combox that triggers an update of form's recordsource. And because neither an error is raised nor parameter input prompt appears, likely the WHERE clause is returning False (i.e., no matching records) and hence no rows are returned.
The reason can likely be due to the combobox [Forms]![fSearches]![cEmploee] which show Employee's surname but is bound to the unique ID as the default setup of Access' comboboxes (if using wizard). See Data tab of combobox's properties in Design View.
The reason for this hidden bound field is users never know the unique ID of a record but do know the value (i.e., name). So when they select the recognized name they are really selecting the corresponding unique ID. Therefore, consider adjusting WHERE condition accordingly where ID is the unique table ID field which matches the bound field of combobox.
Forms("fResultsCases").RecordSource = "SELECT * FROM tCases WHERE [ID] = [Forms]![fSearches]![cEmploee];"
Forms("fResultsCases").Recalc
Forms("fResultsCases").Form.Requery ' USUALLY THE RECORDSOURCE UPDATE CALL

Answer 2

After about ten days of "struggle" with this brainteaser, I decided to post this question to ask for help. Fortunatelly #Parfait has involved with my problem and with his/her accurate remarks helped me understand my mistakes. It also helped me Ken Sheridan's post here. So I am posting my answer just for future reference. #Parfait, I sincerely thank you for your time.
So the problem in this case was primarily understanding how relationships between tables affect data types. If you want to connect a textfield of tableA to tableB, then there are two cases. If the primary key in tableB is number then textfield becomes number. If the primary key in tableB is text then textfield remains text.
In my case it was the first one. Specifically the field [tCases]![assignedTo] after creating relationship with table [tEmployee], was turned automatically into number (It still shows the surname but contains the corresponding primary key in tEmployee). On the contrary combobox [cEmploee] still contained text. This why this line:
Forms("fResultsCases").RecordSource = "SELECT * FROM tCases WHERE [assignedTo] = [Forms]![fSearches]![cEmploee];"
was not returning any record as #Parfait successfully guessed.
At this point there were two possible solutions:
1) Set surname as primary key to agree with combobox contents.
delete the relationship between [tCases]![assignedTo] and [tEmployee].
set field [tEmployee]![surname] (which is text) as primary key in table [tEmployee].
create a new relationship between [tCases]![assignedTo] and [tEmployee].
I did not try this solution though, as a problem would occur if 2 employees had the same surname. So I suggest following the second.
2) Keep the same primary key and use it to match the records from tableA to the surname from tableB.
To achieve this you have to inform access, that you want the records from tableA that have the ID, while in tableB this ID corresponds to the surname inserted in the combobox (hope this makes sense). In other words create a recordset of both tables (union query). For this purpose I replaced the above refered line of code with the following:
Forms("fResultsCases").RecordSource = "SELECT tCases.* FROM tCases INNER JOIN tEmployee ON tCases.[assignedTo] = tEmployee.[employeeID] " & _
"WHERE tEmployee.[surname]=[Forms]![fSearches]![cEmploee] AND tCases![assignedTo]=[tEmployee]![employeeID];"
Hope this saves some time from other people. Have a nice day!