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MAC addresses in JavaScript
...ince any server-side programming language allows you do get access the ARP table, even indirectly (e.g. through a subprocess). I think "client-side language" would work better...
– kirbyfan64sos
Oct 6 '16 at 19:51
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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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What Java ORM do you prefer, and why? [closed]
..._ID = a.ID);
And how it can be expressed in jOOQ:
// Alias the author table
TAuthor a = T_AUTHOR.as("a");
// Use the aliased table in the select statement
create.selectFrom(a)
.whereExists(create.selectOne()
.from(T_BOOK)
.whe...
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...
创建增量同步Oracle物化视图问题 - 数据库(内核) - 清泛网 - 专注C/C++及内核技术
...个表上建立物化视图日志如“CREATE MATERIALIZED VIEW LOG ON T_tablename;”，再到数据库B上创建数据库链接和快速刷新的物化视图如“create materialized view mv_tablename refresh fast on demand start with sysdate next sysdate+1/288 as select * from T_tablename@dblink_...
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 ....................................................
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.
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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...