Dave's FileMaker® Pro Newsletter
FileMaker Data Parsing:
Separation, Commonality, and Distinction
by Dave Dowling, FileMaker database consultant

Commonality: What do all of the target data fields have in common?

Suppose we wanted to send personalized form letters to all of the people in our example database above. We want to create a single form letter, but we want the salutation in every copy of that letter to include the first name of the recipient (e.g., Dear First Name, etc.). How would we grab the first name from every record of our example database? Here's our example database again:

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"John", "Sanders", "555-1234"
"George", "Bailey", ""
"Melissa", "Smith Waters", "555-7890"
"Billy Bob", "", "555-5678"

The key to isolating this particular data field (First Name) is in "commonality". What does each First Name field have in common with every other First Name field in each of our four records? Well, let's think about that together. Here are a some things to consider:

1. Overview: Where in the order of our fields does the First Name field fall? Answer: This is an easy one. The First Name field is the first field in each of our four records.

2. Separation: Is the first field in each record preceded by a carriage return? Answer: It may appear that this is the case, but the First Name field in our first record is preceded by nothing. Every other iteration of the First Name field, however, is preceded by a carriage return. In terms of separation, every First Name field in our database will be preceded by nothing or a carriage return, and each will be followed by a comma. Actually, it's important to note here that each First Name field will be followed by two commas before the next carriage return, which marks the end of the record. We'll see shortly why this is important.

3. Commonality: What do all First Name fields in our database have in common that no other fields in the database have? Answer: The separation patterns that we determined in the answer to our previous question become the common characteristics of each First Name field. Those distinguishing characteristics are: a) each First Name field is preceded by either nothing (the beginning of the database) or a carriage return, and b) each First Name field is followed by a comma.

4. Summary: Besides the First Name field, do any other fields in our database share these characteristics? For example, is any Last Name or Phone Number field preceded by nothing? Answer: No. Is any Last Name of Phone Number field directly preceded by a carriage return? Answer: No. Is any Last Name or Phone Number field directly followed by a comma? Answer: Yes. However, since the First Name field is preceded by unique characters AND is followed by a comma, that field is distinct from the other fields in the database.

So where does this leave us? Well, we now know that each of the First Name fields in our database has character sets that are distinct, and are not shared with either of the other fields in our database. Commonality and distinction are not based solely on preceding or trailing characters, but on both combined. More on that in the next section.

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Copyright 2003, Dave Dowling. All rights reserved.