最近需要用到MySQL 5.7中的JSON,总结一下MySQL中关于JSON的内容

参考:

11.6 The JSON Data Type

12.16 JSON Functions

JSON Function Reference

Functions That Create JSON Values

JSON_ARRAY([val[, val] ...])

构造并返回一个JSON数组

mysql> SELECT JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME());
+---------------------------------------------+
| JSON_ARRAY(1, "abc", NULL, TRUE, CURTIME()) |
+---------------------------------------------+
| [1, "abc", null, true, "11:30:24.000000"] |
+---------------------------------------------+

JSON_OBJECT([key, val[, key, val] ...])

通过键值对列表返回一个JSON对象

mysql> SELECT JSON_OBJECT('id', 87, 'name', 'carrot');
+-----------------------------------------+
| JSON_OBJECT('id', 87, 'name', 'carrot') |
+-----------------------------------------+
| {"id": 87, "name": "carrot"} |
+-----------------------------------------+

JSON_QUOTE(json_val)

产生JSON字符串

mysql> SELECT JSON_QUOTE('null'), JSON_QUOTE('"null"');
+--------------------+----------------------+
| JSON_QUOTE('null') | JSON_QUOTE('"null"') |
+--------------------+----------------------+
| "null" | "\"null\"" |
+--------------------+----------------------+
mysql> SELECT JSON_QUOTE('[1, 2, 3]');
+-------------------------+
| JSON_QUOTE('[1, 2, 3]') |
+-------------------------+
| "[1, 2, 3]" |
+-------------------------+

Functions That Search JSON Values

JSON_CONTAINS(json_doc, val[, path])

返回0 or 1来表示一个特定的值是否在目标JSON文档中

mysql> SET @j = '{"a": 1, "b": 2, "c": {"d": 4}}';
mysql> SET @j2 = '';
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.a');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.a') |
+-------------------------------+
| 1 |
+-------------------------------+
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.b');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.b') |
+-------------------------------+
| 0 |
+-------------------------------+ mysql> SET @j2 = '{"d": 4}';
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.a');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.a') |
+-------------------------------+
| 0 |
+-------------------------------+
mysql> SELECT JSON_CONTAINS(@j, @j2, '$.c');
+-------------------------------+
| JSON_CONTAINS(@j, @j2, '$.c') |
+-------------------------------+
| 1 |
+-------------------------------+

JSON_CONTAINS_PATH(json_doc, one_or_all, path[, path] ...)

返回0 or 1来表示一个JSON文档是否包含一个或多个给定的数据

参数:

  • 'one': 1 if at least one path exists within the document, 0 otherwise.
  • 'all': 1 if all paths exist within the document, 0 otherwise.
mysql> SET @j = '{"a": 1, "b": 2, "c": {"d": 4}}';
mysql> SELECT JSON_CONTAINS_PATH(@j, 'one', '$.a', '$.e');
+---------------------------------------------+
| JSON_CONTAINS_PATH(@j, 'one', '$.a', '$.e') |
+---------------------------------------------+
| 1 |
+---------------------------------------------+
mysql> SELECT JSON_CONTAINS_PATH(@j, 'all', '$.a', '$.e');
+---------------------------------------------+
| JSON_CONTAINS_PATH(@j, 'all', '$.a', '$.e') |
+---------------------------------------------+
| 0 |
+---------------------------------------------+
mysql> SELECT JSON_CONTAINS_PATH(@j, 'one', '$.c.d');
+----------------------------------------+
| JSON_CONTAINS_PATH(@j, 'one', '$.c.d') |
+----------------------------------------+
| 1 |
+----------------------------------------+
mysql> SELECT JSON_CONTAINS_PATH(@j, 'one', '$.a.d');
+----------------------------------------+
| JSON_CONTAINS_PATH(@j, 'one', '$.a.d') |
+----------------------------------------+
| 0 |
+----------------------------------------+

JSON_EXTRACT(json_doc, path[, path] ...)

从JSON文档返回数据,注意5.7.9以上用->代替

mysql> SELECT c, JSON_EXTRACT(c, "$.id"), g
> FROM jemp
> WHERE JSON_EXTRACT(c, "$.id") > 1
> ORDER BY JSON_EXTRACT(c, "$.name");
+-------------------------------+-----------+------+
| c | c->"$.id" | g |
+-------------------------------+-----------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 |
| {"id": "4", "name": "Betty"} | "4" | 4 |
| {"id": "2", "name": "Wilma"} | "2" | 2 |
+-------------------------------+-----------+------+
3 rows in set (0.00 sec) mysql> SELECT c, c->"$.id", g
> FROM jemp
> WHERE c->"$.id" > 1
> ORDER BY c->"$.name";
+-------------------------------+-----------+------+
| c | c->"$.id" | g |
+-------------------------------+-----------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 |
| {"id": "4", "name": "Betty"} | "4" | 4 |
| {"id": "2", "name": "Wilma"} | "2" | 2 |
+-------------------------------+-----------+------+
3 rows in set (0.00 sec)

->符号可以用在非select中,表示某个JSON key的value

mysql> ALTER TABLE jemp ADD COLUMN n INT;
Query OK, 0 rows affected (0.68 sec)
Records: 0 Duplicates: 0 Warnings: 0 mysql> UPDATE jemp SET n=1 WHERE c->"$.id" = "4";
Query OK, 1 row affected (0.04 sec)
Rows matched: 1 Changed: 1 Warnings: 0 mysql> SELECT c, c->"$.id", g, n
> FROM jemp
> WHERE JSON_EXTRACT(c, "$.id") > 1
> ORDER BY c->"$.name";
+-------------------------------+-----------+------+------+
| c | c->"$.id" | g | n |
+-------------------------------+-----------+------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 | NULL |
| {"id": "4", "name": "Betty"} | "4" | 4 | 1 |
| {"id": "2", "name": "Wilma"} | "2" | 2 | NULL |
+-------------------------------+-----------+------+------+
3 rows in set (0.00 sec) mysql> DELETE FROM jemp WHERE c->"$.id" = "4";
Query OK, 1 row affected (0.04 sec) mysql> SELECT c, c->"$.id", g, n
> FROM jemp
> WHERE JSON_EXTRACT(c, "$.id") > 1
> ORDER BY c->"$.name";
+-------------------------------+-----------+------+------+
| c | c->"$.id" | g | n |
+-------------------------------+-----------+------+------+
| {"id": "3", "name": "Barney"} | "3" | 3 | NULL |
| {"id": "2", "name": "Wilma"} | "2" | 2 | NULL |
+-------------------------------+-----------+------+------+
2 rows in set (0.00 sec)

->符号还可以用在json数组中

mysql> CREATE TABLE tj10 (a JSON, b INT);
Query OK, 0 rows affected (0.26 sec) mysql> INSERT INTO tj10
> VALUES ("[3,10,5,17,44]", 33), ("[3,10,5,17,[22,44,66]]", 0);
Query OK, 1 row affected (0.04 sec) mysql> SELECT a->"$[]" FROM tj10;
+--------------+
| a->"$[]" |
+--------------+
| 44 |
| [22, 44, 66] |
+--------------+
2 rows in set (0.00 sec) mysql> SELECT * FROM tj10 WHERE a->"$[]" = 3;
+------------------------------+------+
| a | b |
+------------------------------+------+
| [3, 10, 5, 17, 44] | 33 |
| [3, 10, 5, 17, [22, 44, 66]] | 0 |
+------------------------------+------+
2 rows in set (0.00 sec)

->符号如果没有匹配的key,可以用NULL表示

mysql> SELECT * FROM tj10 WHERE a->"$[][]" IS NOT NULL;
+------------------------------+------+
| a | b |
+------------------------------+------+
| [3, 10, 5, 17, [22, 44, 66]] | 0 |
+------------------------------+------+ mysql> SELECT a->"$[][]" FROM tj10;
+--------------+
| a->"$[][]" |
+--------------+
| NULL |
| 44 |
+--------------+
2 rows in set (0.00 sec)

JSON_KEYS(json_doc[, path])

列出所有KEY或指定KEY

mysql> SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}');
+---------------------------------------+
| JSON_KEYS('{"a": 1, "b": {"c": 30}}') |
+---------------------------------------+
| ["a", "b"] |
+---------------------------------------+
mysql> SELECT JSON_KEYS('{"a": 1, "b": {"c": 30}}', '$.b');
+----------------------------------------------+
| JSON_KEYS('{"a": 1, "b": {"c": 30}}', '$.b') |
+----------------------------------------------+
| ["c"] |
+----------------------------------------------+

JSON_SEARCH(json_doc, one_or_all, search_str[, escape_char[, path] ...])

查找元素,返回位置

  • 'one': The search terminates after the first match and returns one path string. It is undefined which match is considered first.

  • 'all': The search returns all matching path strings such that no duplicate paths are included. If there are multiple strings, they are autowrapped as an array. The order of the array elements is undefined.

mysql> SET @j = '["abc", [{"k": "10"}, "def"], {"x":"abc"}, {"y":"bcd"}]';

mysql> SELECT JSON_SEARCH(@j, 'one', 'abc');
+-------------------------------+
| JSON_SEARCH(@j, 'one', 'abc') |
+-------------------------------+
| "$[]" |
+-------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', 'abc');
+-------------------------------+
| JSON_SEARCH(@j, 'all', 'abc') |
+-------------------------------+
| ["$[0]", "$[].x"] |
+-------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', 'ghi');
+-------------------------------+
| JSON_SEARCH(@j, 'all', 'ghi') |
+-------------------------------+
| NULL |
+-------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '');
+------------------------------+
| JSON_SEARCH(@j, 'all', '') |
+------------------------------+
| "$[][].k" |
+------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$');
+-----------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$') |
+-----------------------------------------+
| "$[][].k" |
+-----------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$[*]');
+--------------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$[*]') |
+--------------------------------------------+
| "$[][].k" |
+--------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$**.k');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$**.k') |
+---------------------------------------------+
| "$[][].k" |
+---------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$[*][0].k');
+-------------------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$[*][0].k') |
+-------------------------------------------------+
| "$[][].k" |
+-------------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$[1]');
+--------------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$[1]') |
+--------------------------------------------+
| "$[][].k" |
+--------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '', NULL, '$[1][0]');
+-----------------------------------------------+
| JSON_SEARCH(@j, 'all', '', NULL, '$[1][0]') |
+-----------------------------------------------+
| "$[][].k" |
+-----------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', 'abc', NULL, '$[2]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', 'abc', NULL, '$[2]') |
+---------------------------------------------+
| "$[].x" |
+---------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%a%');
+-------------------------------+
| JSON_SEARCH(@j, 'all', '%a%') |
+-------------------------------+
| ["$[0]", "$[].x"] |
+-------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%');
+-------------------------------+
| JSON_SEARCH(@j, 'all', '%b%') |
+-------------------------------+
| ["$[0]", "$[].x", "$[].y"] |
+-------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[0]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[0]') |
+---------------------------------------------+
| "$[]" |
+---------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[2]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[2]') |
+---------------------------------------------+
| "$[].x" |
+---------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', NULL, '$[1]');
+---------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', NULL, '$[1]') |
+---------------------------------------------+
| NULL |
+---------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', '', '$[1]');
+-------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', '', '$[1]') |
+-------------------------------------------+
| NULL |
+-------------------------------------------+ mysql> SELECT JSON_SEARCH(@j, 'all', '%b%', '', '$[3]');
+-------------------------------------------+
| JSON_SEARCH(@j, 'all', '%b%', '', '$[3]') |
+-------------------------------------------+
| "$[].y" |
+-------------------------------------------+

Functions That Modify JSON Values

JSON_ARRAY_APPEND(json_doc, path, val[, path, val] ...)

在JSON数组指定位置追加元素,并返回结果

mysql> SET @j = '["a", ["b", "c"], "d"]';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$[1]', 1);
+----------------------------------+
| JSON_ARRAY_APPEND(@j, '$[1]', 1) |
+----------------------------------+
| ["a", ["b", "c", 1], "d"] |
+----------------------------------+
mysql> SELECT JSON_ARRAY_APPEND(@j, '$[0]', 2);
+----------------------------------+
| JSON_ARRAY_APPEND(@j, '$[0]', 2) |
+----------------------------------+
| [["a", 2], ["b", "c"], "d"] |
+----------------------------------+
mysql> SELECT JSON_ARRAY_APPEND(@j, '$[1][0]', 3);
+-------------------------------------+
| JSON_ARRAY_APPEND(@j, '$[1][0]', 3) |
+-------------------------------------+
| ["a", [["b", 3], "c"], "d"] |
+-------------------------------------+ mysql> SET @j = '{"a": 1, "b": [2, 3], "c": 4}';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$.b', 'x');
+------------------------------------+
| JSON_ARRAY_APPEND(@j, '$.b', 'x') |
+------------------------------------+
| {"a": 1, "b": [2, 3, "x"], "c": 4} |
+------------------------------------+
mysql> SELECT JSON_ARRAY_APPEND(@j, '$.c', 'y');
+--------------------------------------+
| JSON_ARRAY_APPEND(@j, '$.c', 'y') |
+--------------------------------------+
| {"a": 1, "b": [2, 3], "c": [4, "y"]} |
+--------------------------------------+ mysql> SET @j = '{"a": 1}';
mysql> SELECT JSON_ARRAY_APPEND(@j, '$', 'z');
+---------------------------------+
| JSON_ARRAY_APPEND(@j, '$', 'z') |
+---------------------------------+
| [{"a": 1}, "z"] |
+---------------------------------+

JSON_ARRAY_INSERT(json_doc, path, val[, path, val] ...)

在JSON数组指定位置插入元素,并返回结果

mysql> SET @j = '["a", {"b": [1, 2]}, [3, 4]]';
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[1]', 'x');
+------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[1]', 'x') |
+------------------------------------+
| ["a", "x", {"b": [1, 2]}, [3, 4]] |
+------------------------------------+
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[100]', 'x');
+--------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[100]', 'x') |
+--------------------------------------+
| ["a", {"b": [1, 2]}, [3, 4], "x"] |
+--------------------------------------+
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[1].b[0]', 'x');
+-----------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[1].b[0]', 'x') |
+-----------------------------------------+
| ["a", {"b": ["x", 1, 2]}, [3, 4]] |
+-----------------------------------------+
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[2][1]', 'y');
+---------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[2][1]', 'y') |
+---------------------------------------+
| ["a", {"b": [1, 2]}, [3, "y", 4]] |
+---------------------------------------+
mysql> SELECT JSON_ARRAY_INSERT(@j, '$[0]', 'x', '$[2][1]', 'y');
+----------------------------------------------------+
| JSON_ARRAY_INSERT(@j, '$[0]', 'x', '$[2][1]', 'y') |
+----------------------------------------------------+
| ["x", "a", {"b": [1, 2]}, [3, 4]] |
+----------------------------------------------------+

JSON_INSERT(json_doc, path, val[, path, val] ...)

若键值对不在JSON对象中,则插入并返回

mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]');
+----------------------------------------------------+
| JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]') |
+----------------------------------------------------+
| {"a": 1, "b": [2, 3], "c": "[true, false]"} |
+----------------------------------------------------+

JSON_MERGE(json_doc, json_doc[, json_doc] ...)

合并json数据并返回结果

mysql> SELECT JSON_MERGE('[1, 2]', '[true, false]');
+---------------------------------------+
| JSON_MERGE('[1, 2]', '[true, false]') |
+---------------------------------------+
| [1, 2, true, false] |
+---------------------------------------+
mysql> SELECT JSON_MERGE('{"name": "x"}', '{"id": 47}');
+-------------------------------------------+
| JSON_MERGE('{"name": "x"}', '{"id": 47}') |
+-------------------------------------------+
| {"id": 47, "name": "x"} |
+-------------------------------------------+
mysql> SELECT JSON_MERGE('', 'true');
+-------------------------+
| JSON_MERGE('', 'true') |
+-------------------------+
| [1, true] |
+-------------------------+
mysql> SELECT JSON_MERGE('[1, 2]', '{"id": 47}');
+------------------------------------+
| JSON_MERGE('[1, 2]', '{"id": 47}') |
+------------------------------------+
| [1, 2, {"id": 47}] |
+------------------------------------+

JSON_REMOVE(json_doc, path[, path] ...)

删除并返回结果

mysql> SET @j = '["a", ["b", "c"], "d"]';
mysql> SELECT JSON_REMOVE(@j, '$[1]');
+-------------------------+
| JSON_REMOVE(@j, '$[1]') |
+-------------------------+
| ["a", "d"] |
+-------------------------+

JSON_REPLACE(json_doc, path, val[, path, val] ...)

替换并返回结果,如果不存在则无操作

mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]');
+-----------------------------------------------------+
| JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]') |
+-----------------------------------------------------+
| {"a": 10, "b": [2, 3]} |
+-----------------------------------------------------+

JSON_SET(json_doc, path, val[, path, val] ...)

set insert replace三者比较

  • JSON_SET() replaces existing values and adds nonexisting values.
  • JSON_INSERT() inserts values without replacing existing values.
  • JSON_REPLACE() replaces only existing values.
mysql> SET @j = '{ "a": 1, "b": [2, 3]}';
mysql> SELECT JSON_SET(@j, '$.a', 10, '$.c', '[true, false]');
+-------------------------------------------------+
| JSON_SET(@j, '$.a', 10, '$.c', '[true, false]') |
+-------------------------------------------------+
| {"a": 10, "b": [2, 3], "c": "[true, false]"} |
+-------------------------------------------------+
mysql> SELECT JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]');
+----------------------------------------------------+
| JSON_INSERT(@j, '$.a', 10, '$.c', '[true, false]') |
+----------------------------------------------------+
| {"a": 1, "b": [2, 3], "c": "[true, false]"} |
+----------------------------------------------------+
mysql> SELECT JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]');
+-----------------------------------------------------+
| JSON_REPLACE(@j, '$.a', 10, '$.c', '[true, false]') |
+-----------------------------------------------------+
| {"a": 10, "b": [2, 3]} |
+-----------------------------------------------------+

Functions That Return JSON Value Attributes

返回JSON相关属性,不常用,直接参考文档

MySQL 5.7 reference about JSON的更多相关文章

  1. MySQL :: MySQL 5.0 Reference Manual :: 14.4 The MEMORY (HEAP) Storage Engine

    MySQL :: MySQL 5.0 Reference Manual :: 14.4 The MEMORY (HEAP) Storage Engine The MEMORY (HEAP) Stora ...

  2. 使用python将mysql数据库的数据转换为json数据

    由于产品运营部需要采用第三方个推平台,来推送消息.如果手动一个个键入字段和字段值,容易出错,且非常繁琐,需要将mysql的数据转换为json数据,直接复制即可. 本文将涉及到如何使用Python访问M ...

  3. MySQL 5.7 Reference Manual :: 4.5.4 mysqldump & mysql — Database Backup & Restore Program

    MySQL :: MySQL 5.7 Reference Manual :: 4.5.4 mysqldump — A Database Backup Programhttps://dev.mysql. ...

  4. MySQL :: MySQL 8.0 Reference Manual :: B.6.4.3 Problems with NULL Values https://dev.mysql.com/doc/refman/8.0/en/problems-with-null.html

    MySQL :: MySQL 8.0 Reference Manual :: B.6.4.3 Problems with NULL Values https://dev.mysql.com/doc/r ...

  5. [转帖 ]MySQL 5.7 新特性 JSON

    MySQL 5.7 新特性 JSON 的创建,插入,查询,更新 作者: 我不是鱼 (2016-08-31 16:13)分类: MySQL   标签: MySQL JSON MySQL JSON 应用 ...

  6. MySQL 5.7开始支持JSON,那还有必要使用MongoDB存JSON吗?请列出你的观点/理由。

    一.观点A:支持MySQL存储JSON MongoDB不支持事务,而MySQL支持事务 MySQL相对MongoDB而言,MySQL的稳定性要优于MongoDB MySQL支持多种存储引擎 二.观点B ...

  7. VSCode package.json warning: Problems loading reference 'https://json.schemastore.org/package'...

    报错内容 Problems loading reference 'https://json.schemastore.org/package': Unable to load schema from ' ...

  8. #MySQL 5.7.8 支持Json类型

    As of MySQL 5.7.8, MySQL supports a native JSON data type that enables efficient access to data in J ...

  9. MySQL 5.7 深度解析: JSON数据类型使用

    http://www.actionsky.com/docs/archives/156  2015年12月25日  杨涛涛 JSON (JavaScriptObject Notation) 是一种轻量级 ...

随机推荐

  1. Unity加入Android广告小结

    在Unity游戏加入广告大致有以下几种方式: 导入Android Jar包 导出游戏为Android项目(在Build时选中Google Android Project,这种方法可以参考将Unity3 ...

  2. DB2表结构DDL脚本导出

    db2look是导出DDL语句脚本的命令,以下是对db2look的一个简单介绍. 语法:db2look -d <数据库名> -e -t <表名> -o <文件名>. ...

  3. Cygwin下软件安装 - apt-cyg

    安装了cygwin,但不能像centos上装yum,装东西很不方便.找了下可以用apt-cyg来安装软件. 1.下载apt-cyg $ wget raw.github.com/transcode-op ...

  4. Python pexpect出现错误‘module have no attribute "spawn" 解决办法

    今天我遇到了这个错误,现在将错误总结如下: 1.首先查询一下自己的操作系统,pexpect中的spawn()和run()仅仅运行在POSIX系统上,在WINDOWS下是没有这两个东西的,在官网http ...

  5. hdu 5349 MZL's simple problem

    题目连接 http://acm.hdu.edu.cn/showproblem.php?pid=5349 MZL's simple problem Description A simple proble ...

  6. Java之NIO传输数据

    NIO可谓陈词旧调,不值一提. 但之前都是泛泛而谈, 现在深入应用才知道秘诀所在. 对于SocketChannel有read()与write(),但由于"非阻塞IO"本质, 这二个 ...

  7. Golang的Semicolons

    Semicolons The formal grammar uses semicolons ";" as terminators in a number of production ...

  8. SqlBulkCopy与触发器,批量插入表(存在则更新,不存在则插入)

    临时表:Test /****** 对象: Table [dbo].[Test] 脚本日期: 05/10/2013 11:42:07 ******/ SET ANSI_NULLS ON GO SET Q ...

  9. [译]rabbitmq 2.2 Building from the bottom: queues

    我对rabbitmq学习还不深入,这些翻译仅仅做资料保存,希望不要误导大家. You have consumers and producers under your belt, and now you ...

  10. ios各种手势,很有意思

    转自http://blog.csdn.net/likendsl/article/details/7554150 这哥们很厉害的 一.概述 iPhone中处理触摸屏的操作,在3.2之前是主要使用的是由U ...