What do you understand by database skills?

1. Understanding relational and non-relational databases: Knowledge of data organization principles, differences, and application areas of SQL and NoSQL DBMS (e.g., PostgreSQL, MySQL, MongoDB).
2. Database schema design: Ability to create logical data structures, define tables, fields, data types, primary and foreign keys, normalization.
3. Writing SQL queries: Confident mastery of SQL syntax for CRUD operations (SELECT, INSERT, UPDATE, DELETE), using JOIN, aggregate functions, grouping, sorting, subqueries.
4. Working with ORM (Object-Relational Mapping): Experience using ORM libraries in Python, such as SQLAlchemy or Django ORM, for database interaction through an object-oriented approach.
5. Query optimization: Understanding ways to improve query performance, use of indexes, analysis of execution plans.
6. Transactions: Knowledge of transactional principles (ACID properties), ability to manage transactions to ensure data integrity.
7. Security: Understanding basic security principles when working with databases, preventing SQL injections, managing user access.

# Example of using SQLAlchemy for data retrieval
from sqlalchemy import create_engine, select

# Creating a connection to the database (using SQLite as an example)
engine = create_engine('sqlite:///:memory:')

# Assuming we have a table 'users' with columns 'id' and 'name'
# (in a real application, the schema would be described more formally)

# Executing a simple SELECT query
with engine.connect() as conn:
    # Metadata is often used in SQLAlchemy to describe tables
    # But for simplicity, we'll show an example with raw SQL
    result = conn.execute(text("SELECT id, name FROM users"))
    for row in result:
        print(f"ID: {row.id}, Name: {row.name}")

Skill	Description	Technology Examples
Database schema design	Creating logical table structures and relationships	ER diagrams
SQL queries	Data selection, insertion, updating, deletion	SELECT, INSERT...
ORM	Interacting with DB through object-oriented code	SQLAlchemy, Django
Query optimization	Improving query performance	Indexes, EXPLAIN
Transactions	Ensuring atomicity and data integrity	COMMIT, ROLLBACK
Security	Protecting against vulnerabilities and access control	SQL injection