Create relationship from two different sources to one base

Try using an automation for this.  Set it up so that it triggers whenever any of the relevant fields in Source One are updated, and make it:
1. Find the record in Master with the same email
2. Update that record with the relevant data

And you'd create the same automation but for Source Two

Thanks. I haven't looked at automation but will do so.

Can you not build relationships in Airtable like you can in other database programs?

Hi,
Inter-base connections established via sync.
Connections between tables inside the base - with links.
Their functions are different.
It seems like functionality you described is exactly what 2-way sync doing with "Allow to edit record in source" enabled, but I'm not sure.
Are you talking about 2 different sets of the same-formatted data?
Like 40 records in Source 1  and 60 records in Source 2 and summary of 100 records in Master?
Or you mean all same 100 records in Source 1, 2 and Master? And if you edit something in Source 1,  same change happens in Master and then synced to Source 2?
The first is usual multi-source sync, second is 2-way Sync , new feature with some limitations.

to be honest, I don't understand how automation triggered in Source should find a record in Master if it's 2 different databases. 

Yeap, you'd do that via linked fields: https://support.airtable.com/docs/linking-records-in-airtable

You want the data from "f_name" and "first_name" merged into a single field though, and so using an automation to update the fields seems like the easiest approach (to me anyway!).  If you wanted to use linked fields for this you'd:
1. Create linked fields in Master to Source One and Source Two
2. Create last modified time fields in Source and and Source Two for the "f_name" and "first_name" fields
3. Create lookup fields in Master that display "f_name" and "first_name"
4. Create lookup fields in Master that display the lookup fields from Step 2
5. Create a formula field that will see which lookup field has the latest time, and from there decide whether to use the value from "f_name" or "first_name"

And you'd need to repeat this process for every field you want to display in Master which seems quite tedious

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@Alexey_Gusev 

re: to be honest, I don't understand how automation triggered in Source should find a record in Master if it's 2 different databases. 

Ah, I was assuming Source One and Source Two were tables that were synced into Master.  You're right, that's not mentioned in the original post, sorry!

Alexey_Gusev.

Perhaps an example will help. Currently, with desktop relational database software, I have something like this.

Table 1 = Master list with 30,000 records. Unique field is email

Table 2 or Table 3 = A new database that I bring in. The ONLY thing I know about these databases is that they ALSO have a unique email field. And they also have most of the same fields (f name, l name, company, address, etc)

So, I create a relationship (connection) between Table 1 and Table 2 using the key field of "email" in both. I map similar fields from Table 1 to Table 2 (e.g., f name > first name, l name > last name, company > co, etc.) And I set up the relationship so that if there are matching records (same key exists in both) between Table 1 and Table 2 the following happens:

Any records that exist in Table 2 but not in Table 1 are added to Table 1
If a record exists in both tables, Table 2 will overwrite the data in Table 1.

Basic relational database stuff.

Other than creating a relationship based on unique key in both tables, and mapping the fields, I don't need to do anything else. The updating of Table 1 based on Table 2 is purely due to matching keys (emails). If I reimport new data into Table 2, Table 1 will be automatically updated. Ditto process for Table 3 and Table 1.

Make sense?