MySQL
MySQL , . .
. :
TINYINT 1 , .. -128 127 ( TINYINT UNSIGNED, .. 0..255);
SMALLINT 2 , -32768..32767 (0..65535);
MEDIUMINT 3 , -8388608..8388607 (0..2^24-1);
INT 4 , -2147483648..2147483647 (0..2^32-1);
BIGINT 8 , -2^32..2^32-1 (0..2^64).
:
FLOAT (4 );
DOUBLE (8 ) .
CHAR (, CHAR(6) hello hello, .. );
VARCHAR ( VARCHAR(6) hello hello);
BLOB, TINYBLOB, MEDIUMBLOB, LONGBLOB ;
TEXT, TINYTEXT, MEDIUMTEXT, LONGTEXT ;
ENUM (, ENUM(0,1,2) , );
SET ( SET(0,1,2) , ).
: BOOL, BOOLEAN;
: SERIAL (== BIGINT UNSIGNED NOT NULL AUTO_INCREMENT UNIQUE);
: DATETIME, DATE, TIMESTAMP, TIME, YEAR.
1. :
CREATE DATABASE `db_name`;
, . , "my_database" :
CREATE DATABASE `my_database`;
, MySQL , , (_).
2. , . .. , "attribute" "table", "database1", :
`database1`.`table`.`attribute`
, "database2", :
`database2`.`table`.`attribute`
, , USE , :
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USE `my_database`;
USE :
`my_database`.`table1`
`table1`
3. DROP DATABASE, . , "my_database", :
DROP DATABASE `my_database`;
. , , .
4. , , , SHOW.
1. :
SHOW DATABASES;
2. :
SHOW TABLES;
3. "table_name" :
SHOW CREATE TABLE `table_name`;
, , .
4. :
SHOW GRANTS;
2.
1. CREATE TABLE. ( , , ..) , . :
CREATE TABLE `table_name` (
`__` _ [],
`__` _ [],
...
`__` _ []
);
, . "news" ( , , ):
CREATE TABLE `news` (
`id` MEDIUMINT(8) UNSIGNED PRIMARY KEY NOT NULL AUTO_INCREMENT,
`posted` TIMESTAMP NOT NULL,
`content` TEXT
);
2. DROP TABLE . , "news" :
DROP TABLE `news`;
3. ALTER TABLE. :
3.1. RENAME. , "news" "news_new", :
ALTER TABLE `news` RENAME TO `news_new`;
3.2. ADD COLUMN, . , "news" "author" ( ) :
ALTER TABLE `news` ADD COLUMN `author` VARCHAR(42);
, . , , . , "author" "news" , "author" , :
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ALTER TABLE `news` ADD COLUMN `author` VARCHAR(42) AFTER `id`;
, "AFTER..." "FIRST". "author" "news" :
ALTER TABLE `news` ADD COLUMN `author` VARCHAR(42) FIRST;
3.3. MODIFY, , . , "author" "news" CHAR(42), :
ALTER TABLE `news` MODIFY COLUMN `author` CHAR(42);
3.4. DROP COLUMN. , "author" "news" :
ALTER TABLE `news` DROP COLUMN `author`;
