Issue: Improve Error Handling in Incremental Materialization

[ReemaAlzaid]

Description

The current implementation of incremental materialization in incremental.sql has limited error handling and recovery mechanisms. This issue proposes to enhance error handling to make the materialization more robust and user-friendly.

Current Situation

In the current implementation:

• Error messages are sometimes cryptic and don't provide clear guidance on how to fix issues
• There's limited validation of user inputs and configurations
• The code contains a comment about Python models being "ok" with temporary views
• Error handling for schema changes could be improved

Proposed Changes

1. Add more comprehensive error handling with descriptive error messages
2. Implement better validation of user configurations before executing SQL
3. Improve the handling of Python models with temporary views
4. Add more robust error recovery mechanisms
5. Implement better logging for debugging purposes

Specific Areas to Improve

1. Line 62-72: Improve the handling of Python models with temporary views

   {%- if language == 'python' -%}
     {#--
     This is ok.
     See note in dbt-spark/dbt/include/spark/macros/adapters.sql
     re: python models and temporary views.
   
     Also, why do neither drop_relation or adapter.drop_relation work here?!
     --#}
     {% call statement('drop_relation') -%}
       drop table if exists {{ tmp_relation }}
     {%- endcall %}
   {%- endif -%}

2. Add better error handling for schema changes in line 58:

   {%- do process_schema_changes(on_schema_change, tmp_relation, existing_relation) -%}

3. Add validation for the unique_key parameter when using the merge strategy

Benefits

• More user-friendly error messages
• Reduced debugging time for users
• More robust materialization process
• Better handling of edge cases
• Improved developer experience

Implementation Details

1. Add try-catch blocks where appropriate
2. Enhance validation functions
3. Improve error messages to be more descriptive
4. Document common errors and their solutions
5. Fix the "ok" Python model handling with a more elegant solution