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What is the “N+1 selects problem” in ORM (Object-Relational Mapping)?
... prevent N+1 selects.
Reference: Java Persistence with Hibernate, chapter 13.
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How to avoid the “divide by zero” error in SQL?
... Henrik Staun PoulsenHenrik Staun Poulsen
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Remove specific commit
...ent" is based on the default number of lines from a context diff, which is 3. So if 'myfile' was constructed like this:
$ cat >myfile <<EOF
line 1
junk
junk
junk
junk
line 2
junk
junk
junk
junk
line 3
EOF
$ git add myfile
$ git commit -m "initial check-in"
1 files changed, 11 insertions(...
Capitalize words in string [duplicate]
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edited Apr 21 at 1:35
answered Sep 29 '11 at 3:47
di...
不同品牌的防火墙组成高可靠性集群 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...主机A 上执行命令
route add -host 172.16.110.80 gw 172.16.100.253
route add -host 172.16.110.80 gw 172.16.100.254
在主机B 上执行命令
route add -host 172.16.100.50 gw 172.16.100.253
route add -host 172.16.100.50 gw 172.16.100.254
执行ping 命令 可以通但是...
What are the most common non-BMP Unicode characters in actual use? [closed]
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Linq 多字段排序，二次排序 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...q 多字段排序，二次排序Linq：ordered = source.OrderByDescending( t => t.f1 ).ThenBy( t => t.f2 );类似SQL：select * from t1 order by f1 d...Linq：ordered = source.OrderByDescending( t => t.f1 ).ThenBy( t => t.f2 );
类似SQL：select * from t1 order by f1 desc ,f2 asc
这种写法...
Getting parts of a URL (Regex)
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153
A single regex to parse and breakup a
full URL including query parameters
and anchors e.g...
Get the generated SQL statement from a SqlCommand object?
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23 Answers
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SQL UPDATE all values in a field with appended string CONCAT not working
...+
| id | data |
+------+-------+
| 1 | max |
| 2 | linda |
| 3 | sam |
| 4 | henry |
+------+-------+
4 rows in set (0.02 sec)
mysql> update t set data=concat(data, 'a');
Query OK, 4 rows affected (0.01 sec)
Rows matched: 4 Changed: 4 Warnings: 0
mysql> select * from t;
...