https://en.wikipedia.org/wiki/Merge_(SQL)

A relational database management system uses SQL MERGE (also called upsert) statements to INSERT new records or UPDATE existing records depending on whether condition matches. It was officially introduced in the SQL:2003 standard, and expanded in theSQL:2008 standard.

http://www.midnightdba.com/Jen/2010/10/tip-over-and-partition-by/

OCTOBER 5, 2010 JEN MCCOWN 20 COMMENTS

Here’s a quick summary of OVER and PARTITION BY (new in SQL 2005), for the uninitiated or forgetful…

OVER

OVER allows you to get aggregate information without using a GROUP BY. In other words, you can retrieve detail rows, and get aggregate data alongside it. For example, this query:

SELECT SUM(Cost) OVER () AS Cost
, OrderNum
FROM Orders

Will return something like this:

Cost  OrderNum
10.00 345
10.00 346
10.00 347
10.00 348

Quick translation:

• SUM(cost) – get me the sum of the COST column
• OVER – for the set of rows….
• () – …that encompasses the entire result set.

OVER(PARTITION BY)

OVER, as used in our previous example, exposes the entire resultset to the aggregation…”Cost” was the sum of all [Cost]  in the resultset.  We can break up that resultset into partitions with the use of PARTITION BY:

SELECT SUM(Cost) OVER (PARTITION BY CustomerNo) AS Cost
, OrderNum
, CustomerNo
FROM Orders

My partition is by CustomerNo – each “window” of a single customer’s orders will be treated separately from each other “window”….I’ll get the sum of cost for Customer 1, and then the sum for Customer 2:

Cost  OrderNum   CustomerNo
8.00 345        1
8.00 346        1
8.00 347        1
2.00 348        2

The translation here is:

• SUM(cost) – get me the sum of the COST column
• OVER – for the set of rows….
• (PARTITION BY CustomerNo) – …that have the same CustomerNo.

جهل بسیط

 Common Table Expressions

Using APPLY

 Cross Apply

عملگرهای جبر رابطه ای

عملگرهای معمولی: اجتماع، اشتراک، تفاضل، ضرب کارتزین

عملگرهای خاص: گزینش(تحدید)، پرتو، پیوند، تقسیم

خلاصه جلسه اوّل نهایه

بسم الله الرحمن الرحیم

بالوجدان می فهمیم که واقعیتی وجود دارد و می فهمیم که در شناخت واقعیت خطا می تواند اتفاق بیفتد. تنها برهان می تواند ما را از شک برهاند و به یقین برساند. برهان فقط به کلیات تعلق می گیرد. پس در فلسفه به احوال موجود کلی یا موجود از آن جهت که موجود است می پردازیم. این احوال و صفات نمی تواند خود نا موجود باشد. پس وصف موجود، خود موجود است. حال این وصف یا مساوی موجود مطلیق است مثل خارجیت مطلقه و وحدت مطلقه یا به ضمیمه مقابلش مساوی موجود مطلق است مثل اینکه می گوییم موجود یا خارجی است و یا ذهنی و یا اینکه می گوییم موجود یا واحد است یا کثیر.

پایان جلسه اوّل.

POCO

Plain old CLR object

From Wikipedia, the free encyclopedia

"POCO" redirects here. For other uses, see Poco (disambiguation).

In software engineering, a plain old CLR object (POCO) is a simple object created in the Common Language Runtime (CLR) of the .NET Framework which is unencumbered by inheritance or attributes. This is often used in opposition to the complex or specialised objects that object-relational mapping frameworks often require^[1]. In essence, a POCO does not have any dependency on an external framework and generally does not have any attached behaviour.

دو خطا در SQL Server که الان به آن برخوردم و راه حل آن‏ها

تعریف عضو وارون

تعریف عضو وارون چپ و راست روشن است.

Definition. Let be a semigroup with identity e. Let a E S. If there exists an element b in S such that ab = e = ba,

then b is called the inverse of a, and a is said to be invertible.

Definition. A nonempty set G with a binary operation . on G is called a group jfthefollowing axioms hold:

(i) a(bc) = (ab)cfor all a,b,c E G. (ii) There exists e E G such that ea = afor all a E G. (iii) For every a E G there exists a' G such that a'a = e.

If the binary operation in a group (G,•) is commutative — that is. ab = ba for all a,b E G — then the group is called commutative or abelian.

تا اینجا: یک مجموعه که ضرب شرکت پذیر، عضو خنثی و وارون گروه. اگر ضرب جابجایی گروه آبلی

Let (S,') be a semigroup. Since- is associative, Theorem 4.2 (Chapter 1) holds here, and therefore there is a unique product of any given elements E S, in that order, that are written For any positive integer n we define, as before, a = aa...a (n-fold product), which is called the nih power of a. 

تعریف عضو خنثی

Definition. Let (S. ) be a semigroup. Ifthere is an element e inS such that ex—x=xe for aJixES,

then e is called the identity of the semigroup (S,).

تعریف right identity

 right identity مشابه left identity تعریف می‏ شود.