4. Data Practices

How we define, document, and work with data structures, including database schemas and SQL styles.

---

4.1 DDLs (Data Definition Language)

Table Formalization

• Create and manage database tables, schemas, constraints

Column Definitions

• Data types, naming conventions, purposes
• Keep a data dictionary or catalog

---

4.2 SQL Convention

Style and Formatting

• Uppercase vs lowercase keywords
• Preferred naming conventions (snake_case, etc.)

Guidelines

• Use CTEs, window functions for clarity
• Comment complex queries

Examples

• Provide simple queries that follow the style