MySQL table operations

Storage Engine

• The storage engine is a table type, and MySQL has different processing mechanisms depending on the table type
• Table is equivalent to a file, a record in the table is equivalent to a row of the file, but a record in the table has a corresponding title, called the table field

• Create a table

  Grammar:
  CREATE TABLE Table name (
  Field name 1 type [(width) constraint],
  Field Name 2 Type [(width) constraint],
  Field Name 3 Type [(width) constraint]
  );

  Attention:
  1. Field names cannot be the same in the same table
  2. Width and constraints are optional
  3. Field names and types are required

# Create Data folderMariaDB [(None)]>Create Database DB1 CharSet UTF8;# Toggle FolderMariaDB [(None)]>Use DB1;# Create a file tableMariaDB [DB1]>CREATE TABLE T1 ( - ID int, -Name varchar ( -), -Sex enum (' Male ',' Female '), -Ageint(3) -);#查看db1库下所有表名MariaDB [DB1]>Show tables; # view Table StructureMariaDB [DB1]>Desc T1;+-------+-----------------------+------+-----+---------+-------+|Field|Type|Null|Key|Default|Extra|+-------+-----------------------+------+-----+---------+-------+| ID    | int( One)|YES|     |Null|       ||Name|varchar -)|YES|     |Null|       ||Sex|Enum' Male ',' Female ')|YES|     |Null|       ||Age| int(3)|YES|     |Null|       |+-------+-----------------------+------+-----+---------+-------+# View Some fields in the tableMariaDB [DB1]>SelectID, Name,sex,age fromT1;EmptySet(0.00Sec# View all fields in a tableMariaDB [DB1]>Select*  fromT1;EmptySet(0.00Sec# Insert an entire row into the table fileMariaDB [DB1]>INSERT INTO T1 values -(1,' Egon ', -,' Male '), -(2,' Alex ',Bayi,' Female ') - ;MariaDB [DB1]>Select*  fromT1;+------+------+------+--------+| ID   |Name|Age|Sex|+------+------+------+--------+|    1 |Egon|    - |Male||    2 |Alex|   Bayi |Female|+------+------+------+--------+# Insert data into a table (a specific field)MariaDB [DB1]>INSERT INTO T1 (ID) values -(3), -(4);MariaDB [DB1]>Select*  fromT1;+------+------+------+--------+| ID   |Name|Age|Sex|+------+------+------+--------+|    1 |Egon|    - |Male||    2 |Alex|   Bayi |Female||    3 |Null|Null|Null||    4 |Null|Null|Null|+------+------+------+--------+

MySQL table operations