大约有 43,000 项符合查询结果（耗时：0.0321秒） [XML]
How to get last N records with activerecord?
...e-wise - at least not up to Rails 3.1. SomeModel.last(5) will execute the select statement without a limit, returning all records of SomeModel to Ruby as an array, after which Ruby will pick out the last (5) elements. Efficiency-wise, currently, you want to use limit - particularly if you have pote...
How to fix .pch file missing on build?
...the bottom of the drop-down menu.
At the top left of the Properties Pages,
select All Configurations from the drop-down menu.
Open the C/C++ tree and select Precompiled Headers
Precompiled Header: Select Use (/Yu)
Fill in the Precompiled Header File field. Standard is stdafx.h
Click Okay
If you do n...
Xcode + remove all breakpoints
...l breakpoints.
In Xcode4 press CMD(⌘)+6, in Xcode3 press CMD(⌘)+ALT+B.
Select all breakpoints with CMD(⌘)+A and delete them, like deleting text, with backspace.
There's no step 3 :)
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Convert NSData to String?
...lowing code works for me where pkey is a pointer to an EVP_PKEY:
unsigned char *buf, *pp;
int len = i2d_PrivateKey(pkey, NULL);
buf = OPENSSL_malloc(len);
pp = buf;
i2d_PrivateKey(pkey, &pp);
NSData* pkeyData = [NSData dataWithBytes:(const void *)buf length:len];
DLog(@"Private key in hex (%d...
How do you list the primary key of a SQL Server table?
...
SELECT Col.Column_Name from
INFORMATION_SCHEMA.TABLE_CONSTRAINTS Tab,
INFORMATION_SCHEMA.CONSTRAINT_COLUMN_USAGE Col
WHERE
Col.Constraint_Name = Tab.Constraint_Name
AND Col.Table_Name = Tab.Table_Name
...
Debugging App When Launched by Push Notification
...opdown. (⌘+<)
Than choose your product - 'Run
MyApp.app' on the left.
Select 'Info' tab on the right.
And finally choose "Wait for
MyApp.app to launch" option.
More here in "Customize Executables in the Scheme Editor" section.
EDIT:
In case you miss logs in GDB, see Louis Gerbarg's comment t...
How do I check if an index exists on a table field in MySQL?
...
Try:
SELECT * FROM information_schema.statistics
WHERE table_schema = [DATABASE NAME]
AND table_name = [TABLE NAME] AND column_name = [COLUMN NAME]
It will tell you if there is an index of any kind on a certain column wi...
What is the easiest way to initialize a std::vector with hardcoded elements?
...typesafe, compile time constant
template <typename T, std::size_t N>
char (&sizeof_array( T(&)[N] ))[N]; // declared, undefined
#define ARRAY_SIZE(x) sizeof(sizeof_array(x))
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How to delete or add column in SQLITE?
... as long as you do a create new table first instead of a create from select, it will have all those things.
– John Lord
Jul 3 '19 at 15:28
1
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PostgreSQL query to list all table names?
...
What bout this query (based on the description from manual)?
SELECT table_name
FROM information_schema.tables
WHERE table_schema='public'
AND table_type='BASE TABLE';
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