Posts Tagged ‘Understanding’
Understanding And Buying DDR Memory
May 19th, 2011 | 
Author: 
The DDR SDRAM is an enhanced version of the old school SD RAM. Known as double data rate synchronous dynamic random access memory this chip has a much greater bandwidth to offer to its users. The thing that makes this memory integrated circuit different is that it unlike the other circuits it transfers the data on both the rising and falling edges of the clock signal. This is what makes the DDR Memory Ram highly efficient as it gives you double the speed while maintaining the same frequency on the front side bus.
The DDR memory chips that are acquirable in the market have no architectural differences with regards to the clock frequencies that they have been designed for. The number denoted on the chip is an indication of the speed at which the device will be performing. Underclocking is the phenomenon of making your chip run at a speed lower than that which has been specified. Overclocking is the exact opposite of this phenomenon. Amateurs should however not experiment with their memory chips in this manner as it might lead to damage.
You will find some new chipsets to be making use of dual and quad channel configurations. This is done for the purpose of increasing the bandwidth. In order to reap maximum benefits of a dual channel configuration you should make use of a pair of matching memory modules.
The world wide web offers you a one-of-a-kind opportunity to look for DDR Memory chips for your desktop computer. Some the Personal Memory chipsets acquirable online are:
INDUSTRY STANDARD 1GB PC2100 266MHZ NON-ECC DDR SDRAM
This is a super high calibre 1GB chipset for your desktop computer. It comes with a 184 pin and dual in line memory module configuration. It as gold leads and a phase lock loop that helps the clock driver to reduce the loading. The chipset enters the commands on apiece positive CK edge. The chipset can perform concurrent operations with assist due to the four internal clock inputs. It also comes with an auto precharge option and auto refresh and self refresh modes. You will be healthy to get your hands on this chipset for just .
INDUSTRY STANDARD 512MB PC2100 266MHZ NON-ECC DDR SDRAM
If you are looking for something with a smaller memory capacity then you can grab the above mentioned model for just . This is a special 512MB chipset that has a Non-ECC optimized pin out. It features the dual in line memory module along with gold leads. The four internal banks enable the chipset to run concurrent operations. It has all the standard features of the series and is saint if you are looking for a 512 MB chipset.
INDUSTRY STANDARD 256MB PC2100 266MHZ NON-ECC DDR SDRAM
If you want something even lower than the 512 then you have this particular 256 MB chipset that gives you the same optimum performance. This speedy chipset will help to give your computer a boost and you can get your hands on this one for just .
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Understanding Session Level Messages in Fix Protocol .
I have been working in FIX prescript for nearly 5 years when I started working on FIX prescript I looked upon world wide web for some good tutorial which could supplement or complement lengthy FIX prescript specification there was nothing at that time so when I started my blog I thought to write about my own experience in FIX prescript as short, clear and concise tutorial format. Since I like question answer type of knowledge sharing too I have written some blog post on FIX prescript Interview questions you might find it interesting.
In today’s FIX tutorial we are going to have a look on FIX prescript session level messages. As you guys might know all FIX messages can be broadly classified in two categories Admin messages also called session level messages and Application messages which include Trade, pre trade and post trades messages. Understanding of how FIX session works is very important because until you know the fundamental of FIX Sequence number, how does FIX session gets connected , what are the sequence of messages that flows between Sender Fix Engine and receiver FIX engine you won’t be healthy to swiftly refer any problem related to FIX protocol. FIX specification is very clear about what should FIX engine do on various FIX session connection / disconnection scenario.
Just to revise as per FIX prescript first Sender FIX Engine and receiver FIX engine connects to apiece other on TCP/IP prescript on specified IP and Port via leased line , Radianz link , Virtual Private network(VPN) or via internet. Once TCP Socket level connectivity established Sender application sends Logon (fix attach 35=A MsgType=A) with concurred SenderCompID (fix attach 49) and TargetCompID (fix attach 50). Receiver FIX engine receives this message and authenticate Sender FIX Engine client based upon SenderCompID (fix attach 49) and TargetCompID (fix attach 50) ,if client is genuine successfully then receiver fix engine replies with same sends Logon (fix attach 35=A) message and connection is successfully established and then both FIX engine will send Heartbeat messages (fix attach 35=0) at specified heartbeat interval to keep connection alive. In case receiver FIX engine is not healthy to authenticate client it will send a Logout message (fix attach 35=5) and connection will be terminated though socket connection will still be there. Receiver FIX engine can also send Logout message (fix attach 35=5) if it receives fix message with sequence number lower than it is expecting.
Now let’s see apiece of session level or Admin messages in tiny detail. You can always refer FIX prescript specification document and that is suggested also to get complete description of apiece of these messages.
Some important Session level or Administrative messages specified in FIX specification are following:
Heartbeat:
Heartbeat messages are denoted by MsgType=0 in financial information exchange (FIX) Protocol. Both FIX Session Initiator and FIX Session Acceptor sends apiece other Heartbeat messages to keep FIX session alive on a interval defined by Heartbeat Interval which is usually 30 or 60 seconds. If you see Heartbeat message (FIX attach 35=0) in your FIX Engine log file means your FIX session is up and connected.
Logon:
Logon message is denoted by FIX attach 35=A and it is used to send login message from FIX initiator. As per FIX Protocol once TCP connection between FIX Initiator and FIX Acceptor got established, FIX initiator sends Logon message (tag 35=A) with pre concurred SenderCompID (tag 49) and TargetCompID (tag 50) and with Sequence No (FIX attach 34) anticipating by FIX Acceptor. When FIX Acceptor receives Logon request (MsgType=A) it authenticate FIX session based on CompID specified in FIX Message and Sequence No and reply back with either Logout (tag 35=5) message or Logon(tag 35=A) message based upon result of authentication.
Resend Request
Resend Request (FIX attach 35=2 or MsgType=2) is used for asking of retransmission or replay of lost messages during transmission or due to incorrect sequence number. It’s normally sent by the FIX Engine which is receiving message to initiate the retransmission of messages. FIX Engine uses Resend Request (tag 35=2) if a sequence number gap is detected or if FIX Engine of receiving application lost a message or as a part of initialization process to make sequence number in sync.
Resend Request (FIX attach 35=2 or MsgType=2) can be used to request a single FIX message, a range of FIX messages or all FIX messages subsequent to a particular FIX message.
Its worth noting that sending FIX Engine might like to think about the message type when resending messages; e.g. if a new order is in the resend series and a significant time period has been passed since it was originally sent, the sender FIX Engine might not wish to retransmit the order since market dynamics an price etc might have been changed also this might result in stale order reject which is done by Order Management Systems (OMS). (The Sequence Reset (FIX attach 35=4 or MsgType=4) Also called as Gap Fill is used to skip FIX messages that a sender FIX Engine does not want to resend.)
It is mandatory that the receiving FIX Engine process messages in sequential order, e.g. if FIX message number 11 is missed and 12-13 received, the application should ignore 12 and 13 and ask for a resend of 11-13, or 11 -0 (0 denotes infinity). Second approach is strongly suggested to recover from out of sequence conditions as it grants for faster recovery in the presence of certain race conditions when both sides of FIX Engines are simultaneously attempting to recover a sequence number gap.
Test Request
In financial information exchange also called FIX Protocol Test Request is denoted by FIX attach 35=1 or MsgType=1. Test Request FIX Message is used by FIX Engine to forces a heartbeat from the opposing FIX Engine. The Test Request (FIX attach 35=1) message checks sequence numbers or verifies communication line status. The opposite FIX Engine responds to the Test Request Test Request (FIX attach 35=1) with a Heartbeat (FIX attach 35=0) containing the TestReqID (FIX attach 112).
The TestReqID FIX attach 112) verifies that the counterparty FIX Engine is generating the Heartbeat (FIX attach 35=0) as the result of Test Request (FIX attach 35=1) and not a normal timeout. The opposite FIX Engine includes the TestReqID (FIX attach 112) in the resulting Heartbeat (FIX attach 35=0). Any string can be used as the Heartbeat (FIX attach 35=0) (Some fix engine generally uses a timestamp string).
Session Level Reject
In financial information exchange (FIX) prescript Session level Reject or Reject message is denoted by FIX attach 35=3 or MsgType=3. Session level Reject is used by FIX engine when a fix message is received but can't be properly processed due to a session-level rule violation as specified in FIX Protocol specification document. As an example FIX Engine will use Session level Reject or a reject it receives a FIX message with invalid basic data (e.g. MsgType 35 =$ ) which successfully passes de-encryption, Checksum (FIX attach 10) and BodyLength (FIX attach 9) checks. As a rule FIX messages should be forwarded to the trading application for business level rejections whenever possible.
Rejected messages should be logged into log file and the incoming sequence number must be incremented by FIX Engine.
Its worth noting that receiving FIX Engine should disregard any FIX message which is incorrect , can't be parsed or fails a data integrity check. Processing of the next valid FIX message will cause detection of a sequence number mismatch and a Resend Request (FIX attach 35=2 or MsgType=2) will be generated and passed to counterparty FIX Engine.
Generation and receipt of a Reject (FIX attach 3) message indicates a serious error that might be the result of faulty logic in either the sending or receiving FIX Engine.
If the sending FIX Engine chooses to retransmit the rejected message, it should be assigned a new sequence number (FIX attach 34) and sent with PossResend (FIX attach 97) =Y.
Its recommended to describe the cause of reject in the fix tag Text (FIX Tag 58) which then can be used by receiving FIX engine or developer to refer actual cause of Session level reject (e.g. Price attach is missing in Limit Order).
Below are some scenarios where session-level Reject (FIX Tag 3 or MsgType=3) can be used.
CompID problem: Either FIX Initiator or FIX Acceptor is sending incorrect SenderCompID (tag 49) and TargetCompID (tag 50).
Invalid MsgType: Either FIX initiator or FIX Acceptor is sending MsgType other than specified in FIX Specification for that particular FIX Version e.g. FIX4.2
Incorrect data format for value: If a FIX attach has a data type Timestamp and FIX engine is sending some other data type
Required attach missing: Either FIX Initiator or FIX Acceptor is not sending mandatory FIX attach in a particular FIX message e.g. Price (FIX attach 44) missing in a NewOrderSingle (MsgType=D) message with OrdType =2 i.e. Limit Order.
Invalid attach number: Either FIX initiator or FIX Acceptor is sending any attach other than specified in FIX Specification for that particular FIX Version e.g. FIX4.2
Tag not defined for this message type: Either FIX initiator or FIX Acceptor is sending any attach other than specified in FIX Specification for that particular message type e.g. Sending TestReqID in logout message.
Undefined Tag: In case any of sender FIX engine is sending custom attach and that is not configured or supported by Revenging fix engine.
Tag specified without a value: e.g. 35= and there is no value for that particular fix tag. Its not a valid fix message and so receiving fix engine will reject it.
Sequence Reset
Sequence Reset also called as Gap fill messages is denoted by FIX attach 35=4 or FIX MsgType 35=4. It is used in response to Resend Request (FIX attach 35=2 or MsgType=2) by sending FIX engine to reset the incoming sequence number on the opposing side FIX engine. Sequence Reset message (fix attach 35=4) operates in two different modes one in which GapFillFlag (FIX attach 123) is ‘Y’ also called Sequence Reset – Gap Fill and second mode on which GapFillFlag (FIX attach 123) is ‘N’ or not present also called Sequence Reset – Reset mode. As per FIX prescript specification the “Sequence Reset (fix attach 35=4)-Reset” mode should ONLY be used to recover from a disaster situation which can't be otherwise recovered by “Gap Fill” mode.
The Sequence Reset or GapFill message (fix attach 35=4) can be useful in the following circumstances:
1. While processing Resend Request (FIX attach 35=2 or MsgType=2) sending FIX Engine might select not to send a message (e.g. a stale order). The Sequence Reset (fix attach 35=4) – Gap Fill can be used to fill the place of that message.
2. While processing Resend Request (FIX attach 35=2 or MsgType=2) sending FIX Engine might select not to send a message if all the messages are only administrative or session level messages, because there is no point on resending them in that case also Sequence Reset (fix attach 35=4) – Gap Fill is used to fill the message or sequence gap.
Logout
Logout message is denoted by FIX attach 35=5 or MsgType=5 in FIX prescript specification and it is used to terminate or close any FIX session. In case receiver FIX engine is not healthy to authenticate client it will send a Logout message (fix attach 35=5) and connection will be terminated though socket connection will still be there. Receiver FIX engine can also send Logout message (fix attach 35=5) if it receives fix message with sequence number lower than it is expecting. The Logout message (fix attach 35=5) is used to terminate a FIX session. Termination or disconnection without the exchange of Logout message (fix attach 35=5) messages is treated an abnormal condition.
Exchange of Logout message (fix attach 35=5) before actually terminating or closing the session grants the initiator FIX engine to perform any kind of Sequence Reset (fix attach 35=4) or Gap fill operations that might be required or necessary. Logout initiator should also move for the opposite FIX engine to respond with a confirming Logout message (fix attach 35=5) it can terminate the session in case the remote FIX Engine does not respond within a specified time period.
To read more about FINANCIAL INFORMATION EXCHANGE (FIX) protocol, see my FIX Protocol tutorial series.
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Understanding of the S-curve of technological innovation
Even though the formation of a new technology appears to occur, its development over time, when it comes to pieces that there is a reasonably stable pattern that can ideal be described in terms of performance characteristics.
Power refers to a feature of interest, a product designer, or users of a particular technology. For example, the fiber optic telegram offers the traditional PBX systems in superior voice quality. The speed of a personal is another example of the performance characteristic that is passed in new technologies. Technological abilities are compared to apiece attribute, such as density indicated in the electronics industry (number of transistors per chip) or aircraft speed in miles per hour. The performance of a technology has an established structure in time, which if understood can be very useful in strategic planning. Technological innovation refers to the variation of performance characteristics of a given technology over time.
The life cycle of innovation can be described with the S-curve, the cards again in a different way, namely, growth in income or productivity function of time. In the primeval stages of a particular innovation, growth is relatively slow, since the new product establishes itself. At some point customers begin to demand and output growth increases more rapidly. Incremental innovations or changes in the product grant growth to continue. Towards the end of its life cycle, growth has slowed and might even begin to decline. In later stages, no amount of new investment in producing a normal yield.
The S-curve is derived from half of a normal distribution curve. It is expected that new products are likely to have “life” are. ie, a start-up phase, a rapid increase revenues and decrease. In fact, the vast majority of innovations never the bottom of the curve, and never produce normal returns.
It is important that apiece technology has a number of functions a, is a specific technology over time. As already mentioned, comes to life once a new technology to show the performance characteristics of interest to very tiny improvement in the primeval stages of technology.
This first step is followed by a second phase of very rapid improvement of the characteristic. In the third step, the feature set to improve, but the rate of improvement begins to decline. In the last phase is very tiny visible improvement and the graphics are, the progress prefabricated in the performance characteristic of a technology over time is a form of S.The S-curve of technological innovation consists of four main stages in the development of a performance characteristic.
1 Emergence – (also known as the embryonic stage) shows tiny improvement in key performance characteristics. The technology is working well below their potential. Neither the nature of technology, nor its applicability to market needs can be comprise.Cette new discovery period of a period of slow initial growth characterized. This is the time trials and the initial bugs were worked on the system.
2 Fast improvement – improving an accelerating voltage phase. The period of improved technology is characterized by a rapid and sustainable growth. As the organizations involved in the production, the experience accumulated over time to accelerate the improvement of performance characteristics. The technology is vulnerable to replacement or obsolescence, when new technology is more efficient or created.
3 improved down – refuses improvement
4. Maturity – improvement is very difficult to achieve. The sophisticated technology begins when the upper limit of the technology will be addressed and the slow progress in implementation. That’s when the technology is dictated by factors such as their natural boundaries such as physical limitations.
reached during the first phase, a new technology enters the market, but adoption is limited limited to a small group of pioneers and market niche. As the product has taken over, new features are introduced and refined in order to meet the needs of the widest doable segment of mainstream users. During this intermediate stage where a dominant design later won the loyalty of the market and also place on the standardization of everything from design to manufacturing. The prevailing view in turn, increases the competition that new entrants to create opportunities for new innovations in cost, scope and product performance is based.
This is the period of rapid growth and greater as technology evolves and reaches the general public. In the final phase of the product reaches market saturation.Some examples of technologies that have followed this path can be found are as follows.
technology of vacuum tubes was limited by the size of the pipe and the power consumption of the heated filament. These two factors were natural barriers to electronic conduction in a vacuum tube. Electronics could not overcome these limitations. The advent of semiconductor technology or transistor that grants conduction of electrons in a solid material, changed the physical limits of size and power. Transistor technology has created the life cycle of technology and make noncurrent vacuum tube technology.
Another example is ceramic, higher operating temperatures and a replacement for metals in internal combustion engines used engines, new technology grants superior engine performance. Engine performance can continue after a series of new technologies, apiece with an upper limit of performance parameters of interest.
Reference <verbessern / strong
Narayanan, V. K (2001) Managing technology and innovation as a competitive advantage, Englewood Cliffs, NJ. Prentice Hall
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quick understanding of the functions of Oracle Number
FUNCTIONS Digital Oracle
especially in the activities of all numbers • Fortunately, Oracle provides functions that deal with numbers. • Functions Oracle are concerned with three classes of numbers:
one-of-a-kind values, group values and values-list.
ü one-of-a-kind value is a number, eg 24.45. The U-values group all numbers in a column in a table. ü values list is a series of numbers in the columns of a line. Lets comprehend with an example, think about the Environment plateau below. CityName MinTemp MAXTEMP DatedOn——————————– —— ———> p ——————-</Mumbai 33.33 40.5 12 – Mar-2010
Chennai 32.33 42.50 12-Mar-2010
Calcutta 34.45 38.0 12-Mar-2010
Delhi 36 89 46.89 12-Mar-2010
Mumbai 33.45 45.89 13-Mar-2010
single value is a value in a column.
Group values , the values of a column is, for example apiece rows.for, all column values MinTemp. list of values is a set of values in the columns of a particular line. For example, 33.33 and 40.5 of the first row of the plateau above. functions act individual values. Wed function description— —————————— ———– ———————————— — ———– —
value1 + value2 + This function adds with value1 value2.
value1 – value2 here -. Function Subtract value2 from value1value1 value2 * here * function, multiplied by value1 value2.
value1 / value2 Here / function, stated value1 value2. ABS (value) Returns the absolute value, ie, back valued. SIGN (value) Returns1 if the value is positive,
-1 if the value is negative,
0, if the value is zero.
CEIL (value) Returns Integer, slightly greater than or equal to the specified value. FLOOR (value) Returns integer just below or equal to the given value. MOD (value, divisor) Returns, memory value / divider. NVL (replacement value) Vice value if the value is zero. POWER (value, exponent) returns with an exponent value. SQRT (value) Returns, square root of the valueis TRUNC (value, precision), the truncated value to the precision.
ROUND (value, precision) are rounded to the precision.Before we can be examples to comprehend “this double sense. Dual is a virtual plateau of Oracle database that is used to test SQL queries.
Let us work a few examples of individual values, the use of functions in this letter are blue, where the results of Oracle, if appropriaterunning SQL> 6 + 2 from dual;.
6 + 2——–
8
SQL> choose 6-2 in double;> 2.6
——
4
SQL> choose 6 * 2 double
6 * 2
——-
12
SQL> choose 2.6 of double
6 / 2 Wed ————–
121
ABS SQL> choose (121) of double;> </p ABS (121)
————-
121
ABS SQL> choose (-121) twice
ABS (-121)
—————-
121
SQL> choose Sign (121) double;
SIGN (121)
—————-
1
SQL> choose Sign (-121) double ;>
SIGN (-121) </p ———- ——-
-1
SQL> choose Sign (0) double
SIGN (0)
Wed —————–
0
SQL> choose CEIL (121.22 ) from two
CEIL (121.22)
——————–
122
SQL> SELECT CEIL (-121.22) Double
CEIL (-121.22)
————- —— p — -121
SQL> SELECT CEIL (121) double;
CEIL (121)
p> ————— –
121
SQL> SELECT CEIL (-121) from dual
p> CEIL (-121)
————- —-
-121
SQL> SELECT FLOOR (121.22) from two
FLOOR (121.22)
——– ————- –
121
SQL> SELECT FLOOR (-121.22) Double
FLOOR (-121.22 )
————————
-122
> SQL SELECT FLOOR (121) double;
SOL (121)
——————
121
SQL> SELECT FLOOR (-121) double;
SOL (-121)
————– p —– -121
SQL> choose MOD (10,3) double
MOD (10.3)
—————-
1
SQL> choose MOD ( 10.2) twice
MOD (10.2)
—————– 0
> SQL choose MOD (10,0) double
MOD (10.0)
p —————– March 10
SQL> choose MOD (0.10) twice
MOD (0.10)
p —— ———- 0
SQL> choose MOD (0.0) twice
MOD (0.0)
—————
0
Watch the Environment </table /> p>
CityName MinTemp MAXTEMP DatedOn </p / ————— ———- ———————- —————— ———-> p —-</Secunderabad 27 33 12-Feb-2008
Hyderabad 24 35 23-Nov-2008
Ahmedabad 34 26-Mar-2008 </p My Gaziabad 23 34 24-Sep-2008
/ p> notice the above table, we see that in the row, the value is 3rd in the MAXTEMP column are not available. Now, thanks to the use of the NVL function, we can not replace the data with a value
Choose the study of the city, NVL (MAXTEMP, 33.5) double ;.
CityName MAXTEMP—– ——————————– – -
Secunderabad 33
Hyderabad 35
Ahmedabad 33.5
Gaziabad 34
select
forget
ü NVL function does not update the database. He temporarily replaced and displayed on the screen.
SQL> POWER (2, 3) from DoublePOWER (2.3)
p —————— – Wed 8
SQL> choose SQRT (4) double
SQRT (4)
———- p ——- 2
SQL> SELECT ROUND (34.4556,2) twice
ROUND (34.4556,2)
Wed ————— ————-
34.46
SQL> SELECT ROUND (34.4556,3) twice
ROUND (34.4556,3)
——————- ——— 34.456 p
SQL> SELECT ROUND (-34.4556,2) double;
ROUND (-34.4556,2)
p —————————- -34, 46
SQL> choose TRUNC (34.4556,2) twice
TRUNC (34.4556,2)
p — ————– ———- 34.45
SQL> choose TRUNC (34.4556,3) twice
TRUNC (34.4556,3)
—- ———————–
34.455 </p functions acting group of values. Fri act These functions, which are based on values, a column in all rows of a table.
The most common functions</p
> Feature </p / —————— — ———————– ———————— — ———————– —
AVG (column name) average of all values in the column.
COUNT (ColumnName) -. number of rows or values in a columnSUM (ColumnName) the sum of all values in the column.
MIN (column name) there are at least all the values in this column. MAX (column name) Returns the highest of all values in this column. STDDEV (ColumnName) usual statistical sense. VARIANCE (ColumnName) usual statistical point of view,can “watch the EMP plateau Scott / Tiger Scheme Basic EMPNO ENAME JOB MGR SAL COMM DEPTNO
HireDate
7369 SMITH CLERK 7902 17-Dec-80 800 20 20
7499 ALLEN 20-FEB SELLER 1600 -7698 81 300 30
7521 VENDOR WARD 7698 22-Feb-81 1250 500 30
7566 JONES MANAGER 7839 02-Apr-81 2975 20 20
7654 VENDOR MARTIN 7698 28 – Sep-81 1250 1400 30
7698 BLAKE MANAGER 7839 01-May 2850 at 81 30 30
7782 CLARK MANAGER 7839 09-Jun-81 10 October 2450
7788 SCOTT ANALYST 7566 19-April -87 3000 20 20
7839 KING PRESIDENT 17-Nov-81 5000 10 10
7844 VENDOR-September 08 TURNER 7698 1500 0 -81 30 20
7876 ADAMS CLERK 7788 23-1100-87 20 20
MAY 7900
saint Clerk 7698 03-Dec-81 950 30 30
< 7902 FORD ANALYST 7566 03-Dec-81 3000 20 20
7934 MILLER CLERK 7782 23-Jan-82 1300 October 10
/ p> What are some examples letters Blue in the results of the Oracle database return paid in response to a query
Find the maximum
SQL> SELECT MAX (sal) from EMP
MAX (SAL)
Wed ————–
5000
Get paid the minimum SQL> SELECT MIN (sal) from EMP
MIN (SAL)
p ————— Sat 800
Find the average salary paid
SQL> SELECT AVG (sal) from EMP
AVG (SAL)
——- ———-
2073.21429
Find the total amount paid in salaries to SQL> SELECT SUM (SAL) from EMP
SUM (SAL)
—————–
29 025 </p / strong> use functions is the situation:> </p opportunity to count the number of rows in a plateau when the argument * (star)
SQL> SELECT COUNT (*) from EMP </p ————- —– Sea> p COUNTY (*)
14
Sets the number of acquirable data in a column in a plateau to count.
you reduce the number of null values in the column of the plateau emp mgr?
SQL> SELECT COUNT (mgr) from EMP
COUNT (MGR)
——————–
13
DISTINCT keyword might be used, apiece group function, but their use is increasingly felt, with < COUNT function / strong>. Let us see They apply DISTINCT to find out how many types of jobs acquirable in
emp plateau SQL COUNT> (DISTINCT JOB) selecting EPM COUNT (DISTINCTJOB) p —— —————————- 5 There are 5 types of jobs in the plateau emp.
Grants Write a query for null values in the column plateau emp mgr
learn
SQL> SELECT COUNT (*)-COUNT (mgr) from EMP
COUNT (*)-COUNT (MGR)
p —————— 1
There is a NULL column
Bishop worse in the emp table.
p> Forgetü Asterisk can not with other GROUP function is used, on the other. that count
ü DISTINCT for use with most <COMTE / strong function.
ü COUNTY can be character column or column line where other group functions can be used only with digital data are used. ü Now you should have noticed COUNTY do not perform arithmetic with the values of a column, but it takes certain values in a column or series of lines in a table. ü substitute to DISTINCT is ALL, is the default. List of functions act values Sat These functions operate on values in two or more columns, one row in a plateauThe most common functions in the plateau below
describe
DESCRIPTION OF OPERATIONS
———— ——————- —————- ———————- ———— —————- ———————- ——
MINUS ( value1, value2, value3, ..) returns the smallest value among the values in the argument list.
GREATEST (value1, value2, value3 ..) is the largest value among the values of the argumentlist
Watch the student Mark plateau with columns as a trademark study of the student in Physics, Mathematics,
Chemistry
Physical Chemistry StudentName MathMarks marks bookmarks
————— —– ———————— ——————— —– ———————— ——–
67 76 89 Lova Raju </
Siri 100 99 99
Viji 99 90 88
Koti 98 88 87
/ p> Now, write an application that the students study and receive the highest score screen, under three themes
SQL> study of the student to choose the largest (MathMarks, physics, chemistry marks) that student scores HighestMark
ENAME HIGHESTMARK
————————————-
Lova Raju 89
Siri 100
Viji 99
Koti 98
Make a request that students want to display the study and received the lowest mark, including three subjects
SQL> study the student to choose at least (MathMarks, physics, chemistry marks) that student scores LowestMark
NULL value functions list and a single Value Functions : the same list value functions treat null values as those of the individual securities Funktionen.Single functions nulls occur if a null result functions ist.List NULL generate revenue if a NULL in the list NULLS is -. Group Characteristics Value value functions of the group manage null values differently than a single digit value functions Funktionen.Gruppe ignore nulls and Go Ahead with the result
Forget </ / p
> U ignore the group-valued functions, null p / ü List single-valued functions and value, not ignore nulls.
<p The author is a trainer in Oracle and Java
u can in toch with me @ raju.allu
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5 Tips to Understanding Audio Visual Technology
Audio visual technology can be extremely beneficial in most environments, it can cut costs and help improve productivity because at the end of the day, it’s all about improving communications. In order to utilize AV technology, you must comprehend it.
Video Conferencing:
Video conferencing is one of the most effective ways to cut costs and improve productivity. Face to grappling communications is often needed to strengthen business relations but if your client isn’t local this might cause problems. Video conferencing is not a new technology but it is becoming more advanced and more affordable. An important half an hour meeting at the other end of the country can easily consume a whole day in travel alone, a video conference maybe just as effective and consume just a fraction of the resources. Video conferencing can also help improve communications in-house, particularly if an organisation has several offices, even though telephone conferencing might be more acceptable in this circumstance, video conferencing can offer several advantages over telephone conferences including the capability to make presentations.
Digital Signage:
Digital signage is similar to video conferencing in that it is still communicating through a visual tool except digital signage is just one way. This can also be a highly effective tool. A reception area of an organisation might have a plasma or LCD screen displaying a welcome message and information about that organisation. A call centre providing services for several organisations might have screens to display stats like call inactivity times etc. An organisation that has several screens throughout the offices can be handed over to the CEO to deliver important messages or presentations to the employees.
Costs:
Although new technology is often associated with a high price tag, this is not necessarily the case with AV technology. When you think of your return on investment, how much is the time you spend traveling to meetings worth to you and your organisation? How effective is your current form of mass communication to your employees or customers? If you just need AV technology as a one off, for a trade show for example, it might establish more cost effective to rent the required technology through a trusted event management company.
AV Specialists:
Like any industry you’re not sure of, it can be difficult to know whom to trust. Even though there is no required accreditation scheme in the UK, an organisation in USA called InfoComm, the have an accreditation system called Certified Audio Visual Solutions Provider (CAVSP), most reputable AV specialists in the UK have gained accreditation from this scheme, which assigns either a bronze, silver or gold level to their certificates. As with any new supplier, check for references, they should be chesty to show examples of their previous work. Make sure they wage a full service. Even though you can purchase audio visual solutions over the internet, a specialist AV supplier or consultant will be healthy to comprehend exactly what you want to achieve from your new technology and design and build a system around that need. They will then integrate and project manage that system for you as well as providing any after care needed. Even though you can purchase your new technology in box form or over the World wide web and it maybe initially cheaper, your long term ROI would benefit from an AV specialist.
Future:
One of the biggest worries an organisation might have when it comes to investing in any new technology is its shelf life. With new technology being developed all the time how do you know your new technology won’t be noncurrent tomorrow? The ideal way to combat this is research, if you employ an AV consultant it’s their job to not only know today’s market inside out but tomorrow’s market too. The market is expanding, nowadays web cams are commonplace in the home, and the World wide web is not only expanding the market in general but is developing global collaboration too.
Further Your Understanding of Structure Functionality By Using Truck 3D Models
Most people naturally learn with aid from visual tools. Most people learn by cramming a massive sum of data in a brief period of time. This can mean that students receive only a partial understanding of the make-up and function of a structure, even while remaining healthy to rattle off the obloquy of the various parts and functions of the structure. Engine 3D Models and Truck 3D models can help students learn about structure functionality.
The engine 3d model offers a comparatively affordable manner in which to give students hands on experience of part manipulation. The same would go for the use of a helicopter 3d engine. Students will have the capability to see how the inside of a helicopter works. It is likely then that students will be healthy to make a connection between the visual parts and the descriptions of those parts.
Without this approach of learning, understanding becomes the same as memorization. Reciting back a list of terms does not imply a functional knowledge. Instead it shows a mind that has separated the terms from the larger functioning structure.
Research often show how the one-sided learning that is attempted in the absence of visual tools results in misconceptions, misinformation and unfortunate to employ the acquired knowledge in real world setting. This can also stagnate the student in related studies in which students should possess adequate knowledge to enable them to correlate information from course to course.
By implementing 3d models into more disciplines, students can start to acclimate themselves using the structures for their field well before they are required to be healthy to disassemble and reassemble these structure. 3d models can also impart student confidence with their field of choice, giving them a familiarity that exceeds far beyond textbook learning.
It is self evident that any student who uses engine 3d models or truck 3d models will be superior off in his or her understanding of the inner workings of these objects. These can also open the doorway as visual cues to learning to assess the cause of problems within these structures. This means the advancement towards using knowledge in real world applications through the appropriate level of understanding need to work in fields connected together with these models.
Helicopter 3d models are only several types of models that students can use to further their understanding of an object’s structure functionality. Engine 3d models save students a whole lot quantity of time and money. Obtain truck 3d models and other 3d models at Flatpyramid.com today.
I write about 3d custom models. I have 10 years experience in the 3d industry. I love creating 3d models for games, movies, architectural visualization, and medical anatomy visualization projects. Read more at http://www.flatpyramid.com.
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Understanding Remote Computer Repair Service
now to light, remote personal repair services are in demand and are now the new trend of how people get their personal repaired. There are several good reasons for this type of repair has become as favourite as the fact that they offer a swift and efficient, and they certainly can solve nearly any other type of personal problem.
Whether your personal has problems with his registration, or it is a virus that your personal is infected, or it could be any other type of problem, remote personal repair services are the ideal option for solve the problem. How does it work?
Before continuing, it is certainly a good intent to understand, first, the work of repair service personal remotely. At first it is first necessary that you and invite you install programs that are diagnostic and repair your personal and these programs are also used to oversee the company’s remote personal repair service, the defective personal not from a remote access site.
This grants the repair company to see on your screen, what is wrong with your personal and the remote personal company can share the keyboard with the personal keyboard faulty. Of course, even if remote personal repair service in exchange is your computer, you are the owner of the defective personal or access to your computer, all that happens is that the company Personal Services Remote Service also has access to your computer, which helps diagnose the problem without sending a technician to be physically present on your site. In addition, remote personal repair service is an interactive process and that means is that the owner of the defective personal can terminate the session whenever they want. And after the repair service personal remotely to resolve problems with the personal automatically uninstalled from your personal is complete. at work For service personal repair remotely, it is necessary to have a fast World wide web connection. In addition, remote personal repair services, is also entitled to some repair work around the clock, which is a boon for someone that your personal loses functionality in the middle of the night . With the IT remote repair, the repair can start at any time of day or night. One option, repair service is to minimize the personal to install the ideal and most effective anti-virus. Many of which are common malware circulating on the World wide web have the capability to infect systems and the system of corruption as long as you’re forced to pay for costly personal repairs. It is obvious that you use each weapon in your arsenal to fight against this virus. This means the use of firewalls to monitor e-mail management and help companies of anti-virus software and the strict application of the policy of the employee that everyone using their desktop personalcommit
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