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PostgreSQL create table if not exists
In a MySQL script you can write:
6 Answers
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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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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
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LR性能指标解释 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...1.服务器Linux（包括CPU、Memory、Load、I O）。2.数据库：1.Mysql 2.Oracle（缓存命中、索引、...监控指标
性能测试通常需要监控的指标包括：
1.服务器Linux（包括CPU、Memory、Load、I/O）。
2.数据库：1.Mysql 2.Oracle（缓存命中、索引、单...
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...