table-validation

Table Validation

Use this skill when a table has been created or written and you need to verify both:

• schema contract
• post-write data quality

This skill assumes you can use existing database tools such as describe_table, get_table_ddl, and read_query. Prefer direct validation queries over prose reasoning.

When to use this skill

Activate when you need to validate one or more of:

• object existence
• missing / extra columns
• type or nullability mismatches
• row-count gates
• null ratios
• numeric ranges
• accepted values
• regex / format rules
• uniqueness / duplicate keys

Core workflow

1. Confirm the exact target table and expected grain.
2. Run schema checks first.
3. Run row-count and cheap aggregate checks next.
4. Run duplicate and format checks after the cheap gates pass.
5. Return a compact pass / fail report with observed values and failing sample filters when useful.

Checklist

• Validation sequence: references/checklist.md

Use the checklist to decide which queries to run with existing tools. Do not wait for prebuilt templates; write the smallest useful validation SQL directly with read_query.