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SchemaMapper Filter

  • November 21, 2019
  • 2 replies
  • 33 views

fallingdog
Contributor
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What does the "Blank Attribute Value" do? I am having a hard time finding it in the docs...

 

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2 replies

mark2atsafe
Safer
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  • Safer
  • 2554 replies
  • November 22, 2019

Hi @fallingdog

I've requested the documentation team take a look at this and add this information to the help files.

What I believe it means is as follows...

The SchemaMapper uses a table of lookups, like this:

Old Attribute Name

 

Old Attribute Value

 

New Attribute Name

 

New Attribute Value

 

myOldAttribute

 

1

 

myNewAttribute

 

Road

 

myOldAttribute

 

2

 

myNewAttribute

 

Railway

 

myOldAttribute

 

 

myNewAttribute

 

Unknown

 

 

So, if myOldAttribute has a value 1, it is mapped to a new attribute (myNewAttribute) with a value Road. The question is, what happens if the old attribute is blank (null or empty).

If Blank Attribute Value is set to Ignore, then the feature won't get myNewAttribute at all.

If Blank Attribute Value is set to Don't Ignore, then it will get myNewAttribute with the value Unknown.

In short, Blank Attribute Value tells FME whether to use or ignore features that have an empty value for the source attribute value.

At least, I'm about 95% certain that's what it does. If you find differently, do please let me know!


fallingdog
Contributor
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  • Author
  • Contributor
  • 24 replies
  • November 22, 2019

Hi @fallingdog

I've requested the documentation team take a look at this and add this information to the help files.

What I believe it means is as follows...

The SchemaMapper uses a table of lookups, like this:

Old Attribute Name

 

Old Attribute Value

 

New Attribute Name

 

New Attribute Value

 

myOldAttribute

 

1

 

myNewAttribute

 

Road

 

myOldAttribute

 

2

 

myNewAttribute

 

Railway

 

myOldAttribute

 

 

myNewAttribute

 

Unknown

 

 

So, if myOldAttribute has a value 1, it is mapped to a new attribute (myNewAttribute) with a value Road. The question is, what happens if the old attribute is blank (null or empty).

If Blank Attribute Value is set to Ignore, then the feature won't get myNewAttribute at all.

If Blank Attribute Value is set to Don't Ignore, then it will get myNewAttribute with the value Unknown.

In short, Blank Attribute Value tells FME whether to use or ignore features that have an empty value for the source attribute value.

At least, I'm about 95% certain that's what it does. If you find differently, do please let me know!

@mark2atsafe - Thanks for the feedback.