大约有 40,000 项符合查询结果（耗时：0.0418秒） [XML]
Entity Framework rollback and remove bad migration
...ad migration to the database. I tried, but it was not working, because the table names I specified in original question. The first option I don't like much, because it looks like I would have to change code of the migration. If I do it poorly, I can broke it all down.
– Martin ...
How many database indexes is too many?
...
It depends on the operations that occur on the table.
If there's lots of SELECTs and very few changes, index all you like.... these will (potentially) speed the SELECT statements up.
If the table is heavily hit by UPDATEs, INSERTs + DELETEs ... these will be very slow w...
Facebook database design?
...
Keep a friend table that holds the UserID and then the UserID of the friend (we will call it FriendID). Both columns would be foreign keys back to the Users table.
Somewhat useful example:
Table Name: User
Columns:
UserID PK
Emai...
What are the differences between virtual memory and physical memory?
...perating system creates and deals with these mappings - utilizing the page table, among other data structures to maintain the mappings. Virtual memory mappings are always found in the page table or some similar data structure (in case of other implementations of virtual memory, we maybe shouldn't ca...
SELECT * FROM X WHERE id IN (…) with Dapper ORM
...er supports this directly. For example...
string sql = "SELECT * FROM SomeTable WHERE id IN @ids"
var results = conn.Query(sql, new { ids = new[] { 1, 2, 3, 4, 5 }});
share
|
improve this answer
...
Converting Select results into Insert script - SQL Server [closed]
... a variety of great features - including generating INSERT statements from tables.
Update: for SQL Server Management Studio 2012 (and newer), SSMS Toolpack is no longer free, but requires a modest licensing fee.
share
...
SET versus SELECT when assigning variables?
... @var varchar(20)
set @var = 'Joe'
set @var = (select name from master.sys.tables where name = 'qwerty')
select @var /* @var is now NULL */
set @var = 'Joe'
select @var = name from master.sys.tables where name = 'qwerty'
select @var /* @var is still equal to 'Joe' */
...
Is there a combination of “LIKE” and “IN” in SQL?
...an use REGEXP_LIKE (available from Oracle version 10 onwards).
An example table:
SQL> create table mytable (something)
2 as
3 select 'blabla' from dual union all
4 select 'notbla' from dual union all
5 select 'ofooof' from dual union all
6 select 'ofofof' from dual union all
7 ...
Naming convention - underscore in C++ and C# variables
...
Except for teams that want their properties to be immutable.
– ChaosPandion
Jun 28 '10 at 22:34
11
...
Why are unnamed namespaces used and what are their benefits?
...sually better to prefer static linkage, as that doesn't pollute the symbol table. It is better to write
static bool getState(/*...*/);
here. I fell into the same trap (there's wording in the standard that suggest that file-statics are somehow deprecated in favour of anonymous namespaces), but wor...