Ruby 操作 Mysql（4）

franket

发布于 2021-10-19 08:09:33

67501

代码可运行

文章被收录于专栏：技术杂记技术杂记

运行总次数：1

代码可运行

更新数据

2.3.0 :066 > r=client.query("update test set name = 'minitest' where id=12")
 => nil 
2.3.0 :067 > r.class
 => NilClass 
2.3.0 :068 > r=client.query("select * from  test  where id=12")
 => #<Mysql2::Result:0x00000001b3b248 @query_options={:as=>:hash, :async=>false, :cast_booleans=>false, :symbolize_keys=>false, :database_timezone=>:local, :application_timezone=>nil, :cache_rows=>true, :connect_flags=>2147525125, :cast=>true, :default_file=>nil, :default_group=>nil, :host=>"192.168.100.105", :username=>"xxx", :password=>"xxx"}> 
2.3.0 :069 > r.each do |x|
2.3.0 :070 >     puts x 
2.3.0 :071?>   end
{"id"=>12, "name"=>"minitest"}
 => [{"id"=>12, "name"=>"minitest"}] 
2.3.0 :072 >

本地检查

mysql> select * from test where id=12;
+------+----------+
| id   | name     |
+------+----------+
|   12 | minitest |
+------+----------+
1 row in set (0.01 sec)

mysql>

删除数据

2.3.0 :073 > r=client.query("delete  from  test  where id=12")
 => nil 
2.3.0 :074 > r=client.query("select * from  test  where id=12")
 => #<Mysql2::Result:0x00000001960590 @query_options={:as=>:hash, :async=>false, :cast_booleans=>false, :symbolize_keys=>false, :database_timezone=>:local, :application_timezone=>nil, :cache_rows=>true, :connect_flags=>2147525125, :cast=>true, :default_file=>nil, :default_group=>nil, :host=>"192.168.100.105", :username=>"xxx", :password=>"xxx"}> 
2.3.0 :075 > r.each do |x|
2.3.0 :076 >     puts x 
2.3.0 :077?>   end
 => [] 
2.3.0 :078 >

查询数据

2.3.0 :082 > r=client.query("select * from  test  limit 10")
 => #<Mysql2::Result:0x00000001c72800 @query_options={:as=>:hash, :async=>false, :cast_booleans=>false, :symbolize_keys=>false, :database_timezone=>:local, :application_timezone=>nil, :cache_rows=>true, :connect_flags=>2147525125, :cast=>true, :default_file=>nil, :default_group=>nil, :host=>"192.168.100.105", :username=>"xxx", :password=>"xxx"}> 
2.3.0 :083 > r.each do |x|
2.3.0 :084 >     puts x 
2.3.0 :085?>   end
{"id"=>1, "name"=>"hello1"}
{"id"=>2, "name"=>"hello2"}
{"id"=>3, "name"=>"hello3"}
{"id"=>4, "name"=>"hello4"}
{"id"=>5, "name"=>"hello5"}
{"id"=>6, "name"=>"hello6"}
{"id"=>7, "name"=>"hello7"}
{"id"=>8, "name"=>"hello8"}
{"id"=>9, "name"=>"hello9"}
{"id"=>10, "name"=>"hello10"}
 => [{"id"=>1, "name"=>"hello1"}, {"id"=>2, "name"=>"hello2"}, {"id"=>3, "name"=>"hello3"}, {"id"=>4, "name"=>"hello4"}, {"id"=>5, "name"=>"hello5"}, {"id"=>6, "name"=>"hello6"}, {"id"=>7, "name"=>"hello7"}, {"id"=>8, "name"=>"hello8"}, {"id"=>9, "name"=>"hello9"}, {"id"=>10, "name"=>"hello10"}] 
2.3.0 :086 >

可以对这个结果集做些手脚，以更方便操作

2.3.0 :111 > r.class
 => Mysql2::Result 
2.3.0 :112 > r.to_a.class
 => Array 
2.3.0 :113 > r.to_a[1]
 => {"id"=>2, "name"=>"hello2"} 
2.3.0 :114 > r.to_a[1]["id"]
 => 2 
2.3.0 :115 > r.to_a[1]["name"]
 => "hello2" 
2.3.0 :116 > r.to_a[0]["name"]
 => "hello1" 
2.3.0 :117 > r.to_a[9]["id"]
 => 10 
2.3.0 :118 >