データベースの講義6日目です。
【参考テキスト】
【講義内容】
【ワンポイント】
ビューの作成
CREATE VIEW CityJapan AS SELECT * FROM City WHERE CountryCode = 'JPN';
ビューの削除
DROP VIEW IF EXISTS CityJapan;
Query OK, 0 rows affected, 1 warning (0.00 sec)
ERROR 1051 (42S02): Unknown table 'world.cityjapan'
【今日の積み上げ】
‐ データベースの基礎
データベースの講義5日目です。
【参考テキスト】
【講義内容】
【ワンポイント】
mysql> help For information about MySQL products and services, visit: http://www.mysql.com/ For developer information, including the MySQL Reference Manual, visit: http://dev.mysql.com/ To buy MySQL Enterprise support, training, or other products, visit: https://shop.mysql.com/ List of all MySQL commands: Note that all text commands must be first on line and end with ';' ? (\?) Synonym for `help'. clear (\c) Clear the current input statement. connect (\r) Reconnect to the server. Optional arguments are db and host. delimiter (\d) Set statement delimiter. ego (\G) Send command to mysql server, display result vertically. exit (\q) Exit mysql. Same as quit. go (\g) Send command to mysql server. help (\h) Display this help. notee (\t) Don't write into outfile. print (\p) Print current command. prompt (\R) Change your mysql prompt. quit (\q) Quit mysql. rehash (\#) Rebuild completion hash. source (\.) Execute an SQL script file. Takes a file name as an argument. status (\s) Get status information from the server. system (\!) Execute a system shell command. tee (\T) Set outfile [to_outfile]. Append everything into given outfile. use (\u) Use another database. Takes database name as argument. charset (\C) Switch to another charset. Might be needed for processing binlog with multi-byte charsets. warnings (\W) Show warnings after every statement. nowarning (\w) Don't show warnings after every statement. resetconnection(\x) Clean session context. For server side help, type 'help contents'
【今日の積み上げ】
‐ データベースの基礎
データベースの講義4日目です。
【参考テキスト】
【講義内容】
【ワンポイント】
コネクション数の確認
SHOW STATUS LIKE 'Threads_connected';
出力結果
+-------------------+-------+ | Variable_name | Value | +-------------------+-------+ | Threads_connected | 1 | +-------------------+-------+ 1 row in set (0.00 sec)
文字コードの確認
SHOW VARIABLES LIKE '%chara%';
出力結果
+--------------------------+-------------------------------+ | Variable_name | Value | +--------------------------+-------------------------------+ | character_set_client | cp932 | | character_set_connection | cp932 | | character_set_database | utf8mb4 | | character_set_filesystem | binary | | character_set_results | cp932 | | character_set_server | utf8mb4 | | character_set_system | utf8 | | character_sets_dir | C:\Dev\mysql8\share\charsets\ | +--------------------------+-------------------------------+ 8 rows in set, 1 warning (0.01 sec)
テーブルステータスの確認
SHOW TABLE STATUS FROM meat_shop WHERE Name='meats' \G
出力結果
*************************** 1. row ***************************
Name: meats
Engine: InnoDB
Version: 10
Row_format: Dynamic
Rows: 11
Avg_row_length: 1489
Data_length: 16384
Max_data_length: 0
Index_length: 0
Data_free: 0
Auto_increment: 12
Create_time: 2020-10-23 12:00:26
Update_time: 2020-10-26 10:57:48
Check_time: NULL
Collation: utf8_general_ci
Checksum: NULL
Create_options:
Comment:
1 row in set (0.00 sec)
【今日の積み上げ】
‐ データベースの基礎
