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Performing user authentication in Java EE / JSF using j_security_check
...thenticate users based on username and MD5-hashed passwords in my database table:
http://blog.gamatam.com/2009/11/jdbc-realm-setup-with-glassfish-v3.html
Note: the post talks about a user and a group table in the database. I had a User class with a UserType enum attribute mapped via javax.persiste...
Why use a READ UNCOMMITTED isolation level?
... sense for reading data will never be modified. Trying to use that to read tables that would be written to means that you will in practice read something that gets rolled back. It's not just that you are reading data that's a few seconds old, but you ....................................................
How to use Oracle ORDER BY and ROWNUM correctly?
...ory, in Oracle, you need to limit the results manually when you have large tables and/or tables with same column names (and you don't want to explicit type them all out and rename them all). Easy solution is to figure out your breakpoint and limit that in your query. Or you could also do this in the...
Ruby on Rails: How do I add a not null constraint to an existing column using a migration?
In my Rails (3.2) app, I have a bunch of tables in my database but I forgot to add a few not null constraints. I've googled around but I can't find how to write a migration which adds not null to an existing column.
...
Omit rows containing specific column of NA
...
It is possible to use na.omit for data.table:
na.omit(data, cols = c("x", "z"))
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Extracting hours from a DateTime (SQL Server 2005)
...dd(hour,12,time_received)
else time_received
END
from table
works
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boost Composite keys - C/C++ - 清泛网 - 专注C/C++及内核技术
...lational databases, composite keys depend on two or more fields of a given table The analogous concept in Boost MultiIndex is Composite keys
In relational databases, composite keys depend on two or more fields of a given table. The analogous concept in Boost.MultiIndex is modeled by means of com...
SQLite UPSERT / UPDATE OR INSERT
... there are two ways to accomplish this, depending on the structure of your table and if you have foreign keys restrictions activated to maintain integrity. I'd like to share this in a clean format to save some time to the people that may be in my situation.
Option 1: You can afford deleting the row...
mmap() vs. reading blocks
...r random access, especially if your access patterns are sparse and unpredictable.
Memory maps allow you to keep using pages from the cache until you are done. This means that if you use a file heavily for a long period of time, then close it and reopen it, the pages will still be cached. With read...
CMake使用教程 - C/C++ - 清泛网 - 专注C/C++及内核技术
...ab/testngpp/cmake-2.8.1/Tests/Tutorial/Step1/build3>make
Linking CXX executable Tutorial.exe
[100%] Built target Tutorial
可以运行一下Turorial.exe：
D:/Projects/Lab/testngpp/cmake-2.8.1/Tests/Tutorial/Step1/build3>Tutorial.exe
Tutorial.exe Version 1.0
Usage: Tutorial.exe number
D:/Pr...