SQL Database

A SQL database (relational database) stores data in tables of rows and columns, with relationships between tables defined via foreign keys. SQL (Structured Query Language) is used to query, insert, update, and delete data. Examples include PostgreSQL, MySQL, and SQLite.

SQL databases enforce a schema - the structure of each table must be defined before inserting data, and all records must conform to it. This strictness ensures data integrity and makes relational queries (joins across tables) fast and predictable.

When ingesting API data into a SQL database, you define a table schema matching the response structure and insert records on each API call. For data that changes - like property prices or product listings - you decide whether to update existing records in place or insert new rows for each change, depending on whether you need history.