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how to add records to has_many :through association in rails
...mer.new(params[:customer])
@cust.houses << House.find(params[:house_id])
Or when creating a new house for a customer:
@cust = Customer.new(params[:customer])
@cust.houses.create(params[:house])
You can also add via ids:
@cust.house_ids << House.find(params[:house_id])
...
MySQL和MongoDB设计实例进行对比 - 大数据 & AI - 清泛网 - 专注C/C++及内核技术
...数表来单独保存。
CREATE TABLE IF NOT EXISTS `mobiles` (
`id` int(10) unsigned NOT NULL AUTO_INCREMENT,
`name` VARCHAR(100) NOT NULL,
`brand` VARCHAR(100) NOT NULL,
PRIMARY KEY (`id`)
);
CREATE TABLE IF NOT EXISTS `mobile_params` (
`id` int(10) unsigned NOT NUL...
两种js滑动门(tab切换)效果 - 源码下载 - 清泛网 - 专注C/C++及内核技术
...d: #fff;
text-align: center;
margin: 0;
}
.nTab{
float: left;
width: 960px;
margin: 0 auto;
border-bottom:1px #AACCEE solid;
background:#d5d5d5;
background-position:left;
background-repeat:repeat-y;
margin-bottom:2px;
}
.nTab .TabTitle{
clear: both;
height: 22px;
ov...
Rails raw SQL example
...
side note: records_array will be of different types for different database adapters. If you're using PG, it will be an instance of PG::Result, not Array.
– tybro0103
Jan 14 '14 at 17:28
...
How to UPSERT (MERGE, INSERT … ON DUPLICATE UPDATE) in PostgreSQL?
...em in useful detail.
In general you must choose between two options:
Individual insert/update operations in a retry loop; or
Locking the table and doing batch merge
Individual row retry loop
Using individual row upserts in a retry loop is the reasonable option if you want many connections concurre...
In CMake, how can I test if the compiler is Clang?
...
A reliable check is to use the CMAKE_<LANG>_COMPILER_ID variables. E.g., to check the C++ compiler:
if (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
# using Clang
elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
# using GCC
elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Intel")
# using ...
Remove Primary Key in MySQL
...erty before dropping the key:
ALTER TABLE user_customer_permission MODIFY id INT NOT NULL;
ALTER TABLE user_customer_permission DROP PRIMARY KEY;
Note that you have a composite PRIMARY KEY which covers all three columns and id is not guaranteed to be unique.
If it happens to be unique, you can m...
How to pull a random record using Django's ORM?
...anager):
def random(self):
count = self.aggregate(count=Count('id'))['count']
random_index = randint(0, count - 1)
return self.all()[random_index]
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Update multiple rows in same query using PostgreSQL
... as c(column_b, column_a, column_c)
where c.column_b = t.column_b;
sql fiddle demo
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android get all contacts
How can I get all the names of the contacts in my Android and put them into array of strings?
8 Answers
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