Database MySQL common command review

--View Database

show databases;

--Create a database
Create database ' name ';

--Delete Database
drop database name ';

--Select Library
Use ' Library name ';

--View your current library
Select Database ();

--View All tables
Show tables;

--Delete Table
drop table name;

--View table structure
DESC table name;

--View the Build table statement
Show create table ' name ';

--Clear Table data
TRUNCATE table ' name ';

--PRIMARY key
PRIMARY KEY

--Cannot be empty
Not NULL

--Can be empty
Null

-The only
UNIQUE

--Self-increment
Auto_increment

--Default value
DEFAULT

--Unsigned
UNSIGNED

--0 padding
Zerofill

--Modify Table name
ALTER table Old table name RENAME [to] new table name

--Modify the data type of the field
ALTER Table name MODIFY property name data type [integrity constraint]

--Modify field names
ALTER table name change old table name new property name new data type

--Add Field
ALTER Table name ADD property 1 data type [integrity data constraint][first | After property name 2]

--delete Field
ALTER Table Table name DROP property name

--Modify the position of the field
ALTER Table name MODIFY property name 1 data type First | After property name 2

--Modify the table's storage engine
ALTER table name engine= storage Engine

--PRIMARY Key index
PRIMARY KEY

--Unique index
UNIQUE

--General Index
INDEX

--Create an index format
Primary KEY (' ID ')--set ID as primary key

Unique Uni_name (' name ')--set name to unique index Uni_name alias

Index Index_tel (' Tel ')--General index Index_tel alias

--Create the index after the table is built
ALTER table name ADD PRIMARY KEY (' field name ');

ALTER table name ADD UNIQUE (' Field name ')

ALTER table name ADD INDEX index_name (' Field name ')

--View Index
SHOW INDEXES from table name

--Delete primary key index
--Delete the self-increment first
ALTER table name MODIFY self-increment field INT UNSIGNED not NULL
--then delete the primary key
ALTER table name DROP PRIMARY KEY

--delete unique index and normal index
DROP index index name on table name

--Add data to the database
INSERT into table name (field name 1, field Name 2, field 3) VALUES (value 1, value 2, value 3);

--Modify data
UPDATE table name SET field name WHERE [condition]

--Delete data
DELETE from table name WHERE [condition]

--Link Database
Mysqli_connect (' hostname ', ' username ', ' password ', ' library name ');

--Set character sets
Musqli_set_charset ();

--Judging the error message
Mysqli_error ();

--Judging the error number
Mysqli_errno ();

--Launch SQL statement
Mysqli_equry ();

--Parse the variable into an associative array
Mysqli_fetch_assoc ();

--Returns the number of result sets
Mysqli_num_rows ();

--Affected rows
Mysqli_affected_rows ();

--Gets the ID of the last insertion
Mysql_free_result ();

Database MySQL common command review