How does a relational database work internally?

How does a relational database store data internally?

A relational database stores data in tables. Tables are organized into columns, and each column stores one type of data (integer, real number, character strings, date, "�). The data for a single "instance"� of a table is stored as a row.

How does a database work internally?

Simply, it reads through each candidate record in the database and matches the expression to the fields. So, if you have "select * from table where name = 'fred'", it literally runs through each record, grabs the "name" field, and compares it to 'fred'.

How does a relational database work?

Whether we are talking about tables or indexes, data is divided into pages of a certain size (e.g. 8 KB). When it needs to read data (tables or indexes), a relational database will map the disk-based pages into memory buffers. When it needs to modify data, the relational database changes the in-memory pages.

How is relational database implemented?

In a relational database, all data are stored and accessed via relations. Relations that store data are called "base relations", and in implementations are called "tables". Other relations do not store data, but are computed by applying relational operations to other relations.

What is the difference between relational and NoSQL databases?

While relational databases have a predefined set of rows and columns, NoSQL databases are structured more like a document. If you know where the information is in the document, you can retrieve it. If the material is still in the document, you can add other, structured information, without having to change the rules.

What is the difference between database and real database?

Of course a real database uses a more sophisticated system involving more types of locks (like intention locks) and more granularities (locks on a row, on a page, on a partition, on a table, on a tablespace) but the idea remains the same.

Are there any articles that explain how database works?

But, there are only a few articles that explain how a database works. You can google by yourself “how does a relational database work” to see how few results there are. Moreover, those articles are short. Now, if you look for the last trendy technologies (Big Data, NoSQL or JavaScript), you’ll find more in-depth articles explaining how they work.