Guess schema in hHiveInput

[ShahabZaidi]

Hi,

When using tHiveInput, we can define the schema manually by clicking the eclipses button. We can define the column names and their datatypes there.

I want to understand that what Guess Schema actually does. When I click the guess schema, I get an error.

I want to understand:

1) What Guess Schema actually do?

2) Can we assign the schema through Guess Schema button click?

3) If answer for 2 is yes, then do we need to define the schema manually through the eclipses button also?

Thanks

[lojdr]

Hello,

What error do you see?

1. TOS connects to target, load structure of the target and try to automatically generate a mapping schema.
2. Yes.
3. No.

Regards

Lojdr

[ShahabZaidi]

When I am clicking the guess schema button, then some Java exception is coming. 

So a schema can only be defined through either:

1) By clicking the eclipses button and enter the column name and data types manually.

or

2) Through Guess schema button. 

Any idea if the schema can be defined by any other means in Studio?

[lojdr]

Hello,

"some Java exception is coming" is not sufficient description of the error.

Regards

Lojdr

[ShahabZaidi]

Hi,

It's Java.lang.classnotfound exception error. 

[shong]

Hi  

Have you defined the query? The guess schema works based on the query you defined. 

Regards

Shong

[ShahabZaidi]

No, I haven't defined the Query through Guess Query button.

I think my answer lies in the question you have asked:

1) I want to understand how Guess schema works and why it is required. 

2) If I have defined schema through eclipses button, then what guess schema will do in case I will click the same (As I am getting an error on same, hence not able to understand it properly).

[shong · Accepted solution]

Hi ShahabZaidi
The 'Guess schema' is not required, we usually define the schema manually or import it from repository. Guess schema works based on the query you have defined.
When to use 'Guess schema?
If you have defined the query, and the schema is not defined yet, you want the program to guess the schema automatically, then you can use this 'Guess schema' button.
Hope it is clear.

Regards
Shong