Tables, rows and columns
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Concept · step 1 of 10
A table is a kind of thing
A relational database keeps data in tables. A table holds one kind of thing, like books, and the board shows one.
- A row is one thing. one book.
- A column is one fact about every row. its title, its number of pages.
- Every row has the same columns. A book cannot have a column that the others do not..
SELECT title, pages FROM books;Two books, two rows; two facts about each, two columns. The query above reads them back. The PostgreSQL tutorial puts the name plainly: relation is essentially a mathematical term for table, which is where "relational" comes from.
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