大约有 6,000 项符合查询结果（耗时：0.0271秒） [XML]
Length of generator output [duplicate]
...pattern could be useful e.g. for some ORM-type object, where you execute a SQL query, then fetch results row-by-row using a cursor (via the iterator), and the __len__ method gets the count from the actual SQL query.
– sleblanc
Mar 28 '13 at 19:54
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TCP 的那些事儿（下） - 更多技术 - 清泛网 - 专注C/C++及内核技术
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设长了，重发就慢，丢了老半天才重发，没有效率，性能差；
设短了，会导致可能并没有丢就重发。于是重发的就快，会增加网络拥塞，导致更多的超时，更多的超时导致更多的重发。
而且，这个超时时间在不同的网络...
常用Linux命令详解（持续更新） - 更多技术 - 清泛网 - 专注C/C++及内核技术
...l_history.TMP .tcshrc anaconda-ks.cfg
显示每个文件详细的信息（包括文件类型、权限、大小、所属组、创建时间等）（ls -l 等同于 ll 命令）
[root@KEDACOM ~]# ls -l
total 64
-rw-r--r-- 1 root root 0 Jun 29 17:50 NRU_CMU_DISK_SIZE_NOTIFY2008
-rw-r--r-- 1...
Reading Excel files from C#
...ironment, to pull large amounts of data from a variety of Excel files into SQL Server Compact. It works very well and it's rather robust.
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answered Sep 8 '10 at 8:45
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Is there any difference between a GUID and a UUID?
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One difference between GUID in SQL Server and UUID in PostgreSQL is letter case; SQL Server outputs upper while PostgreSQL outputs lower.
The hexadecimal values "a" through "f" are output as lower case characters and are case insensitive on input. - rfc41...
How to change owner of PostgreSql database?
I need to change the owner of PostgreSql database.
2 Answers
2
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Permanently Set Postgresql Schema Path
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for those wondering from the psql command line you can list schemas by \dn
– BKSpurgeon
Sep 30 '16 at 1:00
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Oracle Differences between NVL and Coalesce
...null as a from dual
) ;
succeeds.
More information : http://www.plsqlinformation.com/2016/04/difference-between-nvl-and-coalesce-in-oracle.html
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Postgres unique constraint vs index
... "master_unique_idx" UNIQUE, btree (ind_id)
In table description (\d in psql) you can tell unique constraint from unique index.
Uniqueness
Let's check uniqueness, just in case.
test=# insert into master values (0, 0);
INSERT 0 1
test=# insert into master values (0, 1);
ERROR: duplicate key val...
What is a domain specific language? Anybody using it? And in what way?
... system figures out the how.
Examples of DSL include all query languages (SQL, XPath, ...), all template languages (Django, Smarty, ...), shell scripts, especially including stuff like twill, a command driven web browser (mostly used for automated test), data storage and exchange languages (XML, YA...