returned.
What are the methods to optimize scalar queries?One is index optimization and the other is external connections.Isn't the performance of scalar quantum queries worse than external connections at any time.
The following statement is used to convert a scalar quantum query.
Statement 4:
select l.*,(select o.object_name from all_objects o where l.object_id=o.object_id) from v$locked_object l;
Now
the outer left join is missing a plus sign, modify Statement 2 to make it equivalent to Statement 1.
Statement 3:
select l.*,o.object_name from v$locked_object l,all_objects o where l.object_id=o.object_id(+);It is also very slow to change to an equivalent value.
Although Statement 2 is not equivalent, why is Statement 2 faster than Statement 1 and Statement 3? After reading the execution plan for a while, I understood it. In statement 1, OBJ $ uses the entire table, and in statement 2, OBJ $
Statement: For Wang Yangming's mind and quantum physics, I don't know much about it, but I can only know nothing about it. The following are all about it. In the Netease Open Class, I heard Professor Dong ping from Zhejiang University talk about Wang Yangming's learning. He has his own opinions on whether Yangming's learning is idealistic. It is very interesting to have an understanding of the most famous conversation in Yangming Xinxue. Mr. youna
years, humans can calculate it completely !"
The destructive power of quantum physics is amazing. Among the three core principles of Probability Interpretation, uncertainty principle and complementarity principle, the first two destroyed the cause and effect of the classic World. The complementary principle and uncertainty principle combined together destroyed the objectivity and authenticity of the world.
The weather will never be predicted, and t
Qgis is an open source desktop GIS tool written with QT framework. It is a good tool for learning GIS and QT. This article describes how to compile the source code of qgis In ubuntu.
Reference link:
Http://gvision.info/using-qtcreator-with-qgis/
Http://hub.qgis.org/projects/quantum-gis/repository/revisions/master/entry/INSTALL
Environment: Ubuntu 11.10
1. Dependent tool set:
-Cmake> = 2.6.2
-Flex
-Bison >=2.4
Ii. Dependent libraries:
-QT> = 4.4.0
-
Scalar Query
Oracle allows a single-row subquery to be included in the select clause. Using scalar queries can effectively improve performance. When using external connections or using aggregate functions, we can consider the possibility of scalar quantum queries.
1. Cancel the use of external connections
External Connection practices:Select a. username, count (*) from all_users A, all_objects B
Where a. Username = B. Owner (+)
Group by A. Username;
P
' equations have been widely recognized by people even before Hertz experiments have been proven. Many great scientists are impressed by its charm and deeply influenced by it. They have a firm belief in the beauty of science and even believe that for a scientific theory, concise and elegant is more important than accurate experiment data. In any sense, electromagnetic theory is a great theory. Roger ponse (RogerIn his book the Emperor's new mind, Penrose does not hesitate to associate it with Ne
Oracle scalar queries and their own defined functions are sometimes easier to use, and are often used by developers. Small amount of data does not matter. The amount of data is large and there are often performance problems.Here is a test to help you understand the scalar quantum query thoroughly. Sql> CREATE TABLE A (ID int,name varchar2 (10)); Table created. Sql> CREATE TABLE B (ID int,name varchar2 (10)); Table created. Sql> INSERT into a values (1
I just read the article about oracle efficient design. When it comes to Standard Quantum queries in oracle, the performance depends on associated queries, however, I know in SQL server that the performance of associated queries is better than that of scalar queries.
Let's test the performance by executing the statement:
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Set autotrace on
Select a. username
Common operation of variable quantum strings${#string} Returns the length of the $string${#string:p Osition} in $string, start extracting substrings from position $position${#string:p Osition:length} in $string, extract the substring of length $length starting from the position $position${string#substring} deletes the shortest match $substring substring starting at the beginning of the variable $string${string# #substring} deletes the longest matching
Release date:Updated on:
Affected Systems:Schneider Electric Modicon QuantumDescription:--------------------------------------------------------------------------------Bugtraq id: 51605Cve id: CVE-2012-0929, CVE-2012-0930, CVE-2012-0931
Schneider Electric is a company that has been committed to improving customers' performance and daily living standards in the power industry. Schneider Electric Group provides products and services for energy and infrastructure, industry, data centers and network
1. Laser(1) Laser principleEinstein's Radiation Theory:Spontaneous emission: The process by which an atom transitions from an energetic state to a low-energy state and emits photons, i.e. H (v) =e2- E1Stimulated radiation: stimulated radiation light amplification is the basic mechanism of laser generation. N21=b21ρ (v) N2Stimulated absorption: n12=b12ρ (v) N1The relationship between Einstein coefficients A12, B21 and B12:A21n2+b21ρ (v) n2=b12ρ(v) N1(2) necessary conditions for laser generationPa
}ilikesanpanilikeluoswimming[[emailprotected] scripts]#echo${liuyifei%like*}ilikesanpani[[emailprotected] Scripts]#echo${liuyifei%%like*}i========================${string/substring/replace} replaces the first encountered match character${string/#substring/replace} prefix match, must match all, replace a strip${string/%substring/replace} to replace the last encountered match character from the back,[[email protected] scripts]# echo ${liuyifei/like/love}I love Sanpan i like Luo swimming[[email pro
${variable/#substring/replace} if the $string prefix matches $substring, $replace is used instead of matching $substring${variable/%substring/replace} if $string end matches $substring, use $replace instead of match $substring#!/bin/shfor i in $ (ls |grep "jpg$");d Oi=${i/%jpg/mp4}doneResults:[Email protected] ~]# sh for2.sh stu_10299_1_.mp4stu_10299_2_.mp4stu_10299_3_.mp4stu_10299_4_.mp4stu_10299_5_.mp4V. Substitution of variables${value:-word} If the variable value has an assignment, use th
others: The topic gives NOP operation, by N (do Nothing), S (1), C (0), F (reverse) and other basic operations, each operation will produce different heat. The initial string and the target string of the NW group are given, which require the heat to be generated at least to convert the initial string into the target string, and there may be no solution at this time to output "NP"Direct BFS, similar to DFS's brute force enumeration, the queue loops, each time to sweep all the NOP operations, and
(Defprotocol X (cat [this other])Define a protocol, which is similar to the objective-C protocol. Different from Java interfaces.
User => X
{: On-interface user. x,: on user. x,: Sigs {: CAT {: Doc nil,: arglists ([this other]),: Name cat }},: var # 'user/X ,: method-map {: Cat: CAT },: method-builders {# 'user/cat #
User => (extend-type string X (cat [this other] (. Concat this other )))This is the objc style. Define a function as an implementation of a type under a protocol.
User => (Ca
0 reply content:
1. Adhere to the Wheaton rules
The central idea of the Wheaton law is "Don't be a dick", which means not to be a person regardless of others' feelings. Here, what I want to say is that you must be patient with yourOpen SourceProject
The developer sends an SQL statement and generates 236 rows of data at 7 minutes 32 seconds select OT. guest_id, OT. order_id, OT. guest_name, Oct. guest_name, OT. ticket_price, Oct. ticket_price from t_to_order_tickets ot left join (select Oct. *, (
Executable, non-optimized, and messy. Haha, if anyone is in a mood to change it, or if there is a clear implementation in other places, send me a copy back :)========================================================== =================================
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