Jak utworzyć bazę danych w MySQL (Tworzyć MySQL Tabele)

Kroki tworzenia bazy danych w MySQL

A database in MySQL is a named container for tables, views, and related objects. You can create one in two ways:

1) Wykonując proste zapytanie SQL

2) Korzystając z inżynierii przyszłości w MySQL Workbench

As Początkujący SQL, przyjrzyjmy się najpierw metodzie zapytania.

Jak utworzyć bazę danych w MySQL

Oto jak utworzyć bazę danych w MySQL:

CREATE DATABASE to polecenie SQL używane do tworzenia bazy danych w MySQL.

Imagine you need to create a database with the name “movies”. You can create a database in MySQL by executing the following SQL command.

CREATE DATABASE movies;

Note: You can also use the command CREATE SCHEMA instead of CREATE DATABASE.

The statement works only once. Running it again throws an error, so let’s improve the query with more parameters.

JEŚLI NIE ISTNIEJE

Pojedynczy MySQL server can hold many databases. When several people share that server, you may try to create a database with the name of an existing one.

JEŚLI NIE ISTNIEJE instructs the MySQL server to check for a database with the same name before creating it. The database is created only if the name is free; without this clause, MySQL wyrzuca błąd.

CREATE DATABASE IF NOT EXISTS movies;

Once the database name is safe, the next decision is how MySQL should store and compare the text inside it.

Sortowanie i zestaw znaków

A zestaw znaków decides which characters a column can store, while a porównanie jest zestawem rules used in comparison and sorting. Both can be defined at four levels: server, database, table, and column.

The collation you choose depends on the character set. For instance, the latin1 character set uses the latin1_swedish_ci collation, which is the Swedish case-insensitive order.

CREATE DATABASE IF NOT EXISTS movies CHARACTER SET latin1 COLLATE latin1_swedish_ci;

For local languages such as Arabic or Chinese, select the Unicode utf8mb4 character set, which stores every Unicode character, including emoji. In MySQL 8.0, utf8mb4 is the default character set and utf8mb4_0900_ai_ci the default collation.

CREATE DATABASE IF NOT EXISTS movies CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci;

Możesz znaleźć listę wszystkich zestawień i zestawów znaków w tym miejscu.

You can see the list of existing databases by running the following SQL command.

SHOW DATABASES;

With the database in place, you can now add the tables that will actually hold the records.

Jak utworzyć tabelę w MySQL

The CREATE TABLE command is used to create tables in a database.

As the diagram shows, every table belongs to one database. Tables are created with the UTWÓRZ TABELĘ statement, which has the following syntax.

CREATE TABLE [IF NOT EXISTS] `TableName` (`fieldname` dataType [optional parameters]) ENGINE = storage Engine;

TUTAJ

• “CREATE TABLE” is responsible for the creation of the table in the database.
• “[IF NOT EXISTS]” is optional and only creates the table if no matching table name is found.
• “`fieldName`” is the name of the field, and “data Type” defines the nature of the data stored in it.
• “[optional parameters]” is extra information about a field, such as “AUTO_INCREMENT” or NOT NULL.
• “storage Engine” manages the table, normally InnoDB, which supports transactions and foreign keys.

MySQL Utwórz przykład tabeli

Poniżej znajduje MySQL example to create a table in a database:

CREATE TABLE IF NOT EXISTS `MyFlixDB`.`Members` (
  `membership_number` INT AUTO_INCREMENT ,
  `full_names` VARCHAR(150) NOT NULL ,
  `gender` VARCHAR(6) ,
  `date_of_birth` DATE ,
  `physical_address` VARCHAR(255) ,
  `postal_address` VARCHAR(255) ,
  `contact_number` VARCHAR(75) ,
  `email` VARCHAR(255) ,
  PRIMARY KEY (`membership_number`) )
ENGINE = InnoDB;

Uwaga: prawidłowe MySQL słowo kluczowe to AUTO_INCREMENT with an underscore. AUTOINCREMENT należy do SQLite and raises a syntax error in MySQL.

Every column carries a data type, so choose carefully: neither underestimate nor overestimate the range of data you expect.

MySQL Typy danych

Data types define the nature of the data that can be stored in a particular column of a table.

MySQL ma 3 main categories of data types, namely:

1. Numeryczne
2. Tekst
3. Data / godzina

Numeryczne typy danych

Numeric data types are used to store numeric values. It is very important to make sure the range of your data is between the lower and upper boundaries of the numeric data type you pick.

Typy danych tekstowych

As the data type category name implies, these are used to store text values. Always make sure the length of your textual data does not exceed the maximum length of the column.

Date and Time Data Types

Date and time data types store calendar and clock values in a fixed format, which keeps sorting and comparison reliable.

Inne typy danych

Apart from the above, there are some other data types in MySQL.

Now let’s see a query for creating a table which uses all the data types. Study it and identify how each data type is defined in the below create table MySQL przykład.

CREATE TABLE `all_data_types` (
    `varchar` VARCHAR( 20 )  ,
    `tinyint` TINYINT  ,
    `text` TEXT  ,
    `date` DATE  ,
    `smallint` SMALLINT  ,
    `mediumint` MEDIUMINT  ,
    `int` INT  ,
    `bigint` BIGINT  ,
    `float` FLOAT( 10, 2 )  ,
    `double` DOUBLE  ,
    `decimal` DECIMAL( 10, 2 )  ,
    `datetime` DATETIME  ,
    `timestamp` TIMESTAMP  ,
    `time` TIME  ,
    `year` YEAR  ,
    `char` CHAR( 10 )  ,
    `tinyblob` TINYBLOB  ,
    `tinytext` TINYTEXT  ,
    `blob` BLOB  ,
    `mediumblob` MEDIUMBLOB  ,
    `mediumtext` MEDIUMTEXT  ,
    `longblob` LONGBLOB  ,
    `longtext` LONGTEXT  ,
    `enum` ENUM( '1', '2', '3' )  ,
    `set` SET( '1', '2', '3' )  ,
    `bool` BOOL  ,
    `binary` BINARY( 20 )  ,
    `varbinary` VARBINARY( 20 )
) ENGINE = MYISAM;

Najlepsze praktyki tworzenia MySQL Baza danych

A few conventions keep your scripts readable:

• Use upper case letters for SQL keywords, i.e. “DROP SCHEMA IF EXISTS `MyFlixDB`;”
• End all your SQL commands using semicolons.
• Avoid using spaces in schema, table, and field names. Use underscores instead to separate schema, table, or field names.
• Prefer InnoDB over MyISAM for new tables, because InnoDB supports transactions, row-level locking, and foreign keys.

The query method is complete. The second route reaches the same database from a visual model instead of hand-written SQL.

Jak stworzyć MySQL Workbench ER Diagram Forward Engineering

MySQL Workbench posiada narzędzia wspierające inżynierię przyszłości. Inżynieria przyszłości is the technical term that describes the process of translating a logical model into a physical implementation automatically.

Stworzyliśmy Schemat ER w naszym Modelowanie oddziału ratunkowego lesson. We will now use that ER model to generate the SQL scripts that will create our database.

Tworzenie bazy danych MyFlix z modelu MyFlix ER

Step 1) Open the ER model of the MyFlix database które stworzyłeś wcześniej.

Krok 2) Wybierz inżyniera przyszłości

Click on the Database menu and select Forward Engineer.

Step 3) Connection options

The next window allows you to connect to an instance of MySQL server. Click on the stored connection drop-down list and select local host. Click Execute.

Step 4) Select the options shown below

Select the options shown below in the wizard that appears. Click Next.

Step 5) Keep the selections default and click Next

The next screen shows the summary of objects in our EER diagram. Our MyFlix DB has 5 tables. Keep the selections default and click Next.

Krok 6) Revspójrz na skrypt SQL

The window below previews the SQL script that creates our database. Save the script to a *.sql file or copy it to the clipboard, then click Next.

Step 7) Commit progress

The window below appears once the database is created on the selected MySQL server instance. The tables from the ER model now exist physically on the server.

The database along with dummy data is attached. We will use this DB in the lessons that follow. Simply import it in MySQL Workbench to get started.

Kliknij tutaj, aby pobrać MyFlixDB

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