AgentSkillsCN

schema-exploration

用于探索并理解数据库的结构、表、列，以及各表之间的关联关系。

SKILL.md
--- frontmatter
name: schema-exploration
description: For discovering and understanding database structure, tables, columns, and relationships

Schema Exploration Skill

When to Use This Skill

Use this skill when you need to:

  • •Understand the database structure
  • •Find which tables contain certain types of data
  • •Discover column names and data types
  • •Map relationships between tables
  • •Answer questions like "What tables are available?" or "What columns does the Customer table have?"

Workflow

1. List All Tables

Use sql_db_list_tables tool to see all available tables in the database.

This returns the complete list of tables you can query.

2. Get Schema for Specific Tables

Use sql_db_schema tool with table names to examine:

  • •Column names - What fields are available
  • •Data types - INTEGER, TEXT, DATETIME, etc.
  • •Sample data - 3 example rows to understand content
  • •Primary keys - Unique identifiers for rows
  • •Foreign keys - Relationships to other tables

3. Map Relationships

Identify how tables connect:

  • •Look for columns ending in "Id" (e.g., CustomerId, ArtistId)
  • •Foreign keys link to primary keys in other tables
  • •Document parent-child relationships

4. Answer the Question

Provide clear information about:

  • •Available tables and their purpose
  • •Column names and what they contain
  • •How tables relate to each other
  • •Sample data to illustrate content

Example: "What tables are available?"

Step 1: Use sql_db_list_tables

Response:

code
The Chinook database has 11 tables:
1. Artist - Music artists
2. Album - Music albums
3. Track - Individual songs
4. Genre - Music genres
5. MediaType - File formats (MP3, AAC, etc.)
6. Playlist - User-created playlists
7. PlaylistTrack - Tracks in playlists
8. Customer - Store customers
9. Employee - Store employees
10. Invoice - Customer purchases
11. InvoiceLine - Individual items in invoices

Example: "What columns does the Customer table have?"

Step 1: Use sql_db_schema with table name "Customer"

Response:

code
The Customer table has these columns:

- CustomerId (INTEGER) - Primary key, unique customer ID
- FirstName (NVARCHAR) - Customer's first name
- LastName (NVARCHAR) - Customer's last name
- Company (NVARCHAR) - Company name (optional)
- Address, City, State, Country, PostalCode - Location fields
- Phone (NVARCHAR) - Phone number
- Fax (NVARCHAR) - Fax number
- Email (NVARCHAR) - Email address
- SupportRepId (INTEGER) - Foreign key to Employee table

Sample data shows customers like:
- Luís Gonçalves from Brazil
- Leonie Köhler from Germany
- François Tremblay from Canada

Example: "How do I find revenue by artist?"

Step 1: Identify tables needed

  • •Artist (has artist names)
  • •Album (links artists to tracks)
  • •Track (links albums to sales)
  • •InvoiceLine (has sales data)
  • •Invoice (has revenue totals)

Step 2: Map relationships

code
Artist (ArtistId)
  ↓ 1:many
Album (ArtistId, AlbumId)
  ↓ 1:many
Track (AlbumId, TrackId)
  ↓ 1:many
InvoiceLine (TrackId, UnitPrice, Quantity)

Response:

code
To find revenue by artist, you'll need to:
1. Start with the Artist table
2. JOIN to Album on ArtistId
3. JOIN to Track on AlbumId
4. JOIN to InvoiceLine on TrackId
5. SUM the revenue (UnitPrice * Quantity)
6. GROUP BY artist name

This requires the query-writing skill to execute.

Quality Guidelines

For "list tables" questions:

  • •Show all table names
  • •Add brief descriptions of what each contains
  • •Group related tables (e.g., music catalog, transactions, people)

For "describe table" questions:

  • •List all columns with data types
  • •Explain what each column contains
  • •Show sample data for context
  • •Note primary and foreign keys
  • •Explain relationships to other tables

For "how do I query X" questions:

  • •Identify required tables
  • •Map the JOIN path
  • •Explain the relationship chain
  • •Suggest next steps (use query-writing skill)

Common Exploration Patterns

Pattern 1: Find a Table

"Which table has customer information?" → Use list_tables, then describe Customer table

Pattern 2: Understand Structure

"What's in the Invoice table?" → Use schema tool to show columns and sample data

Pattern 3: Map Relationships

"How are artists connected to sales?" → Trace the foreign key chain: Artist → Album → Track → InvoiceLine → Invoice

Tips

  • •Table names in Chinook are singular and capitalized (Customer, not customers)
  • •Foreign keys typically have "Id" suffix and match a table name
  • •Use sample data to understand what values look like
  • •When unsure which table to use, list all tables first