Data models and relationships
A data model describes what information is stored and how its elements relate to one another. In a relational model, data is organised into tables. Keys and relationships connect these tables and give the structure a clear form.
This area follows the path from a practical question to an understandable and maintainable collection of data.
Queries and analysis
A query selects information, joins datasets and prepares results. SQL provides a language for expressing selection conditions, joins and groupings. The meaning of a result also depends on the underlying data model.
Annotated queries, examples of analysis and explanations of data-access design can be published here.
Transactions and persistent storage
A transaction groups several database operations into a logical unit. Organising writes, concurrent use and backups is among the fundamental concerns of operating a database.
Original contributions can address data integrity, permission models, backups or the connection between applications and databases.