CREATE TABLE - building a new shelf

The most important command of the scriptorium is CREATE TABLE. It creates a new, empty shelf ready to receive scrolls.

Basic syntax

1CREATE TABLE table_name (
2  column1 TYPE,
3  column2 TYPE,
4  column3 TYPE
5);

We read it like this: "Build a shelf named table_name, and in it the fields: column1, column2, column3". Each field has its name and its type.

Writing rules

• After the table name we open a round parenthesis

  (

  .
• Inside we list the columns, each on a new line for readability.
• We separate column definitions with commas - but we do NOT put a comma after the last one.
• We close the parenthesis

  )

  and end the whole thing with a semicolon ";".

Definition of a single column

In a column definition we first write the name, and right after it the data type:

1tytul VARCHAR(255)

This means: "the tytul field accepts text up to 255 characters". The order is always this: NAME, then TYPE.

Example: a simple kategorie shelf

1CREATE TABLE kategorie (
2  id INT,
3  nazwa VARCHAR(100)
4);

A shelf

kategorie

was created with two fields:

id

for numbers and

nazwa

for short text. It is still empty - but the plan is ready!

Does the table name matter?

Very much! A table name is the address of the shelf in the Library. You will later use it to retrieve data (

SELECT * FROM kategorie

), add columns or drop the whole shelf. Good names are short, plural (

ksiazki

,

autorzy

,

czytelnicy

) and describe the kind of scrolls stored. We avoid spaces and special characters - instead we use underscores, e.g.

rok_wydania

.

Remember three things

1. Parentheses

   ( )

   enclose the list of columns - without them MySQL reports an error.
2. Commas separate the columns, but there is none after the last one.
3. A semicolon ";" ends the whole statement.

When these three elements are in place, the shelf is built in the blink of an eye!