10分钟了解MySQL5.7对原生JSON的支持与用法

Posted 2020-08-11

Part1:JSON格式的支持

MySQL5.7版本终于支持了原生的JSON格式,即将关系型数据库和文档型NO_SQL数据库集于一身。本文接下来将对这特性分别就MySQL5.7和MariaDB10.1各自实现的方法异同进行介绍和演示。

Part2:创建相应表结构

[[email protected] ~]# mysql -V

mysql  Ver 14.14 Distrib 5.7.15, for linux-glibc2.5 (x86_64) using  EditLine wrapper

mysql> create database helei;
Query OK, 1 row affected (0.00 sec)
mysql> use helei;
Database changed
mysql> create table helei (id int(10) unsigned NOT NULL,context json default null,primary key(id));
Query OK, 0 rows affected (0.02 sec)
mysql> show create table helei \G
*************************** 1. row ***************************
       Table: helei
Create Table: CREATE TABLE `helei` (
  `id` int(10) unsigned NOT NULL,
  `context` json DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.02 sec)

Part3:构造数据&测试

mysql> desc helei;
+---------+------------------+------+-----+---------+-------+
| Field   | Type             | Null | Key | Default | Extra |
+---------+------------------+------+-----+---------+-------+
| id      | int(10) unsigned | NO   | PRI | NULL    |       |
| context | json             | YES  |     | NULL    |       |
+---------+------------------+------+-----+---------+-------+
2 rows in set (0.00 sec)

mysql> insert into helei values(1,‘{"name":"贺磊","age":100}‘),(2,‘{"name":"陈加持","age":30}‘),(3,‘{"name":"于浩","age":28}‘);
Query OK, 3 rows affected (0.00 sec)
Records: 3  Duplicates: 0  Warnings: 0

mysql> select * from helei;
+----+----------------------------------+
| id | context                          |
+----+----------------------------------+
|  1 | {"age": 100, "name": "贺磊"}     |
|  2 | {"age": 30, "name": "陈加持"}    |
|  3 | {"age": 28, "name": "于浩"}      |
+----+----------------------------------+
3 rows in set (0.00 sec)


mysql> select id,JSON_EXTRACT(context,‘$.name‘) name,JSON_EXTRACT(context,‘$.age‘) age from helei;
+----+-------------+------+
| id | name        | age  |
+----+-------------+------+
|  1 | "贺磊"      | 100  |
|  2 | "陈加持"    | 30   |
|  3 | "于浩"      | 28   |
+----+-------------+------+
3 rows in set (0.00 sec)
获取Key-Value

mysql> select id,json_keys(context) from helei;
+----+--------------------+
| id | json_keys(context) |
+----+--------------------+
|  1 | ["age", "name"]    |
|  2 | ["age", "name"]    |
|  3 | ["age", "name"]    |
+----+--------------------+
3 rows in set (0.00 sec)
获取全部Key

mysql> update helei set context=JSON_INSERT(context,‘$.name‘,"贺磊",‘$.address‘,‘beijing‘)where id=1;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from helei;
+----+------------------------------------------------------+
| id | context                                              |
+----+------------------------------------------------------+
|  1 | {"age": 100, "name": "贺磊", "address": "beijing"}   |
|  2 | {"age": 30, "name": "陈加持"}                        |
|  3 | {"age": 28, "name": "于浩"}                          |
+----+------------------------------------------------------+
3 rows in set (0.00 sec)
增加Key-Value

mysql> update helei set context=JSON_SET(context,‘$.name‘,"高穷帅")where id=1;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from helei;
+----+---------------------------------------------------------+
| id | context                                                 |
+----+---------------------------------------------------------+
|  1 | {"age": 100, "name": "高穷帅", "address": "beijing"}    |
|  2 | {"age": 30, "name": "陈加持"}                           |
|  3 | {"age": 28, "name": "于浩"}                             |
+----+---------------------------------------------------------+
3 rows in set (0.00 sec)
变更key-value

mysql> update helei set context=JSON_REMOVE(context,‘$.name‘) where id=1;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

mysql> select * from helei;
+----+------------------------------------+
| id | context                            |
+----+------------------------------------+
|  1 | {"age": 100, "address": "beijing"} |
|  2 | {"age": 30, "name": "陈加持"}      |
|  3 | {"age": 28, "name": "于浩"}        |
+----+------------------------------------+
3 rows in set (0.00 sec)
删除Key-Value

JSON格式存储BLOB的测试

Part1:Dynamic Columns处理方式的异同

①MySQL5.7的动态列JSON格式存储

mysql> insert into helei_blob values(1,‘{"name":"贺磊","age":100}‘),(2,‘{"name":"陈加持","age":30}‘),(3,‘{"name":"于浩","age":28}‘);
Query OK, 3 rows affected (0.01 sec)
Records: 3  Duplicates: 0  Warnings: 0
mysql> select * from helei_blob;
+----+-------------------------------+
| id | blob_col                      |
+----+-------------------------------+
|  1 | {"name":"贺磊","age":100}     |
|  2 | {"name":"陈加持","age":30}    |
|  3 | {"name":"于浩","age":28}      |
+----+-------------------------------+
3 rows in set (0.00 sec)

②MariaDB的动态列JSON格式存储

MariaDB [helei]> create table helei (id int(10) unsigned NOT NULL,context json default null,primary key(id));
ERROR 1064 (42000): You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near ‘json default null,primary key(id))‘ at line 1
可以看到MariaDB并不能直接存储JSON类型。

MariaDB [helei]> show create table helei_blob\G;
*************************** 1. row ***************************
       Table: helei_blob
Create Table: CREATE TABLE `helei_blob` (
  `id` int(10) unsigned NOT NULL AUTO_INCREMENT,
  `blob_col` blob,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
1 row in set (0.00 sec)
ERROR: No query specified

MariaDB [helei]> insert into helei_blob values(5,column_create(‘color‘,‘blue‘,‘size‘,‘XL‘));
Query OK, 1 row affected (0.01 sec)

MariaDB [helei]> select * from helei_blob;
+----+--------------------------------+
| id | blob_col                       |
+----+--------------------------------+
|  1 | {"name":"贺磊","age":100}      |
|  2 | {"name":"陈加持","age":30}     |
|  3 | {"name":"于浩","age":28}       |
|  5 |  	     3 sizecolor!XL!blue |
+----+--------------------------------+
4 rows in set (0.00 sec)
直接查询是乱码需用以下函数查询

MariaDB [helei]> select id,column_json(blob_col) from helei_blob where id =5;
+----+------------------------------+
| id | column_json(blob_col)        |
+----+------------------------------+
|  5 | {"size":"XL","color":"blue"} |
+----+------------------------------+
1 row in set (0.00 sec)

MariaDB [helei]> select id,column_list(blob_col) from helei_blob where id =5;
+----+-----------------------+
| id | column_list(blob_col) |
+----+-----------------------+
|  5 | `size`,`color`        |
+----+-----------------------+
1 row in set (0.00 sec)
获取全部Key

MariaDB [helei]> select id,column_get(blob_col,‘color‘ as char) as color from helei_blob where id =5;
+----+-------+
| id | color |
+----+-------+
|  5 | blue  |
+----+-------+
1 row in set (0.00 sec)
获取Key-Value

MariaDB [helei]> update helei_blob set blob_col=column_add(blob_col,‘sex‘,‘man‘) where id=5;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [helei]> select id,column_json(blob_col) from helei_blob where id=5;
+----+------------------------------------------+
| id | column_json(blob_col)                    |
+----+------------------------------------------+
|  5 | {"sex":"man","size":"XL","color":"blue"} |
+----+------------------------------------------+
1 row in set (0.00 sec)
增加Key-Value

MariaDB [helei]> update helei_blob set blob_col=column_add(blob_col,‘color‘,‘black‘) where id=5;
Query OK, 1 row affected (0.00 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [helei]> select id,column_json(blob_col) from helei_blob where id=5;
+----+-------------------------------------------+
| id | column_json(blob_col)                     |
+----+-------------------------------------------+
|  5 | {"sex":"man","size":"XL","color":"black"} |
+----+-------------------------------------------+
1 row in set (0.00 sec)
更改Key-Value

MariaDB [helei]> update helei_blob set blob_col=column_delete(blob_col,‘sex‘,‘man‘) where id=5;
Query OK, 1 row affected (0.01 sec)
Rows matched: 1  Changed: 1  Warnings: 0

MariaDB [helei]> select id,column_json(blob_col) from helei_blob where id=5;
+----+-------------------------------+
| id | column_json(blob_col)         |
+----+-------------------------------+
|  5 | {"size":"XL","color":"black"} |
+----+-------------------------------+
1 row in set (0.00 sec)
删除Key-Value

——总结——

虽然MySQL5.7和MariaDB10.0/10.1版本对于JSON的支持是比较完整的,不过MongoDB的Sharding功能更加好用,个人更倾向于MongoDB。由于笔者的水平有限，编写时间也很仓促，文中难免会出现一些错误或者不准确的地方，不妥之处恳请读者批评指正。

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