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Best way to store time (hh:mm) in a database
I want to store times in a database table but only need to store the hours and minutes.
I know I could just use DATETIME and ignore the other components of the date, but what's the best way to do this without storing more info than I actually need?
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delete_all vs destroy_all?
I am looking for the best approach to delete records from a table. For instance, I have a user whose user ID is across many tables. I want to delete this user and every record that has his ID in all tables.
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What is the difference between tinyint, smallint, mediumint, bigint and int in MySQL?
... take up different amounts of space and they have different ranges of acceptable values.
Here are the sizes and ranges of values for SQL Server, other RDBMSes have similar documentation:
MySQL
Postgres
Oracle (they just have a NUMBER datatype really)
DB2
Turns out they all use the same specific...
MongoDB Show all contents from all collections
...of your database.
db.stats()
step 5: listing out all the collections(tables).
show collections
step 6:print the data from a particular collection.
db.'collection_name'.find().pretty()
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CSS selector - element with a given child [duplicate]
...do (which helped in my case) is to select elements that have no children:
table td:empty
{
background-color: white;
}
Or have any children (including text):
table td:not(:empty)
{
background-color: white;
}
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What's the difference between equal?, eql?, ===, and ==?
...programming languages, such as Ruby, provide a collection type called hash table. Hash tables are dictionary-like collections which store data in pairs, consisting of unique keys and their corresponding values. Under the hood, those keys are stored as hashcodes. Hash tables are commonly referred to ...
Awk学习笔记 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...置函数
控制流命令
4. awk的环境变量
Table 1. awk的环境变量
变量
描述
$n
当前记录的第n个字段，字段间由FS分隔。
$0
完整的输入记录。
ARGC
命令行参数的数目。
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What's the meaning of interface{}?
...ucted of two words of data:
one word is used to point to a method table for the value’s underlying type,
and the other word is used to point to the actual data being held by that value.
Addendum: This is were Russ's article is quite complete regarding an interface structure:
t...
Cost of len() function
... the most common implementation of the Python language. Here's a link to a table that provides the algorithmic complexity of many different functions in CPython:
TimeComplexity Python Wiki Page
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Get list of databases from SQL Server
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@Gia It does exist as a backwards compatablity view. msdn.microsoft.com/en-us/library/ms179900%28v=SQL.110%29.aspx
– Chris Diver
Aug 7 '11 at 22:26
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