The architect's workshop - CREATE TABLE and INSERT

A master does not only read scrolls - they build new shelves. Let us return to the art of creating tables and filling them with data.

CREATE TABLE - a new shelf

We create a table with the

CREATE TABLE

statement. Each column has a name and a data type:

1CREATE TABLE wydawnictwa (
2  id INT PRIMARY KEY AUTO_INCREMENT,
3  nazwa VARCHAR(100),
4  miasto VARCHAR(100)
5);

The most common data types:

• INT

  - a whole number (e.g. a year, a count).

• VARCHAR(n)

  - short variable-length text up to

  n

  characters (e.g. a title).

• TEXT

  - long text (e.g. a review).

• DECIMAL(8,2)

  - a number with decimal places (e.g. a price).

• DATE

  - a date.

PRIMARY KEY and AUTO_INCREMENT

PRIMARY KEY

is the unique signature of every row.

AUTO_INCREMENT

makes the database assign the next number to each new entry by itself - we do not have to remember it.

INSERT - filling the shelf

We add data with the

INSERT

statement. We can add one row or many at once:

1INSERT INTO czytelnicy (imie, nazwisko, miasto)
2VALUES ('Anna', 'Nowak', 'Kraków'),
3       ('Piotr', 'Lis', 'Gdańsk');

Separate consecutive rows with a comma. This is how the Library grows - shelf by shelf, scroll by scroll!