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  • table lock while creating table using select

    - by shal
    Using mysql version 5.0.18 I am creating a table TT, Client 1 set autocommit = false; start transaction Create table TT select * from PT; PT has tow columns pk bigint not null,name varchar(20) Client 2 set autocommit = false start transaction insert into PT values(123,'text'); While inserting a row in PT , it is waiting for the table Client 1 to commit. I am unable to insert the row. why? Is it possible to insert the row without waiting for Client 1 to commit.

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  • What to do with a big image that's slowing website loading down significantly

    - by Dave
    Hi I'm working on a website that's already been designed by someone else. The designer has used a big image (900x700 100KB) which contains a big logo right across the top, then the background for two columns. This image loads every time a page is loaded as it forms the basis for the website. What should I do with it to improve loading time? I'm considering splitting it up into two or more images, especially the logo on the top. Does splitting up images like that decrease loading time in any significant way? Thanks -edit: Also, all the images are .jpg, would changing this to .gif or .png help anything?

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  • Avoiding seasonality assumption for stl() or decompose() in R

    - by user303922
    Hello everybody, I have high frequency commodity price data that I need to analyze. My objective is to not assume any seasonal component and just identify a trend. Here is where I run into problems with R. There are two main functions that I know of to analyze this time series: decompose() and stl(). The problem is that they both take a ts object type with a frequency parameter greater than or equal to 2. Is there some way I can assume a frequency of 1 per unit time and still analyze this time series using R? I'm afraid that if I assume frequency greater than 1 per unit time, and seasonality is calculated using the frequency parameter, then my forecasts are going to depend on that assumption. names(crude.data)=c('Date','Time','Price') names(crude.data) freq = 2 win.graph() plot(crude.data$Time,crude.data$Price, type="l") crude.data$Price = ts(crude.data$Price,frequency=freq) I want frequency to be 1 per unit time but then decompose() and stl() don't work! dim(crude.data$Price) decom = decompose(crude.data$Price) win.graph() plot(decom$random[2:200],type="line") acf(decom$random[freq:length(decom$random-freq)]) Thank you.

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  • PHP strtotime without leap-years

    - by Christian Sciberras
    With regards to this thread, I've developed a partial solution: function strtosecs($time,$now=null){ static $LEAPDIFF=86400; $time=strtotime($time,$now); return $time-((date('Y',$time)-1968)/4*$LEAPDIFF); } The function is supposed to get the number of seconds given a string without checking leap-years. It does this calculating the number of leap-years 1970 [(year-1986)/4], multiplying it by the difference in seconds between a leap-year and a normal year (which in the end, it's just the number of seconds in a day). Finally, I simply remove all those excess leap-year seconds from the calculated time. Here's some examples of the inputs/outputs: // test code echo strtosecs('+20 years',0).'=>'.(strtosecs('+20 years',0)/31536000); echo strtosecs('+1 years',0).'=>'.(strtosecs('+1 years',0)/31536000); // test output 630676800 => 19.998630136986 31471200 => 0.99794520547945 You will probably ask why am I doing a division on the output? It's to test it out; 31536000 is the number of seconds in a year, so that 19.99... should be 20 and 0.99... should be a 1. Sure, I could round it all and get "correct" answer, but I'm worried about the inaccuracies.

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  • Query in sql involving joins of two table

    - by Satish
    I have two tables reports and holidays. reports: (username varchar(30),activity varchar(30),hours int(3),report_date date) holidays: (holiday_name varchar(30), holiday_date date) select * from reports gives +----------+-----------+---------+------------+ | username | activity | hours | date | +----------+-----------+---------+------------+ | prasoon | testing | 3 | 2009-01-01 | | prasoon | coding | 4 | 2009-01-03 | | prasoon | coding | 4 | 2009-01-06 | | prasoon | coding | 4 | 2009-01-10 | +----------+-----------+---------+------------+ select * from holidays gives +--------------+---------------+ | holiday_name | holiday_date | +--------------+---------------+ | Diwali | 2009-01-02 | | Holi | 2009-01-05 | +--------------+---------------+ Is there any way by which I can output the following? +-------------+-----------+---------+-------------------+ | date | activity | hours | holiday_name | +-------------+-----------+---------+-------------------+ | 2009-01-01 | testing | 3 | | | 2009-01-02 | | | Diwali | | 2009-01-03 | coding | 4 | | | 2009-01-04 | Absent | Absent | | | 2009-01-05 | | | Holi | | 2009-01-06 | coding | 4 | | | 2009-01-07 | Absent | Absent | | | 2009-01-08 | Absent | Absent | | | 2009-01-09 | Absent | Absent | | | 2009-01-10 | coding | 4 | | +-------------+-----------+---------+-------------------+ In other words I want to fill the activity and hours columns with "Absent" on the dates which are neither in table reports nor in table holidays. How can I write a specific query for it. The query should give the output between two specific dates.

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  • Is there a Delphi standard function for escaping HTML?

    - by Mason Wheeler
    I've got a report that's supposed to take a grid control and produce HTML output. One of the columns in the grid can display any of a number of values, or <Any>. When this gets output to HTML, of course, it ends up blank. I could probably write up some routine to use StringReplace to turn that into &lt;Any&gt; so it would display this particular case correctly, but I figure there's probably one in the RTL somewhere that's already been tested and does it right. Anyone know where I could find it?

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  • How to handle customers with multiple addresses in CakePHP

    - by Ryan
    I'm putting together a system to track customer orders. Each order will have three addresses; a Main contact address, a billing address and a shipping address. I do not want to have columns in my orders table for the three addresses, I'd like to reference them from a separate table and have some way to enumerate the entry so I can determine if the addressing is main, shipping or billing. Does it make sense to create a column in the address table for AddressType and enumerate that or create another table - AddressTypes - that defines the address enumeration and link to that table? I have found other questions that touch on this topic and that is where I've taken my model. The problem I'm having is taking that into the cakePHP convention. I've been struggling to internalize the direction OneToMany relationships are formed - the way the documentation states feels backwards to me. Any help would be appreciated, Thanks!

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  • Big-O for calculating all routes from GPS data

    - by HH
    A non-critical GPS module use lists because it needs to be modifiable, new routes added, new distances calculated, continuos comparisons. Well so I thought but my team member wrote something I am very hard to get into. His pseudo code int k =0; a[][] <- create mapModuleNearbyDotList -array //CPU O(n) for(j = 1 to n) // O(nlog(m)) for(i =1 to n) for(k = 1 to n) if(dot is nearby) adj[i][j]=min(adj[i][j], adj[i][k] + adj[k][j]); His ideas transformations of lists to tables His worst case time complexity is O(n^3), where n is number of elements in his so-called table. Exception to the last point with Finite structure: O(mlog(n)) where n is number of vertices and m is the amount of neighbour vertices. Questions about his ideas why to waste resources to transform constantly-modified lists to table? Fast? only point where I to some extent agree but cannot understand the same upper limits n for each for-loops -- perhaps he supposed it circular why does the code take O(mlog(n)) to proceed in time as finite structure? The term finite may be wrong, explicit?

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  • Are there any tools to optimize the number of consumer and producer threads on a JMS queue?

    - by lindelof
    I'm working on an application that is distributed over two JBoss instances and that produces/consumes JMS messages on several JMS queues. When we configured the application we had to determine which threading model we would use, in particular the number of producing and consuming threads per queue. We have done this in a rather ad-hoc fashion but after reading the most recent columns by Herb Sutter in Dr Dobbs (in particular this one) I would like to size our threads in a more rigorous manner. Are there any methods/tools to measure the throughput of JMS queues (in particular JBoss Messaging queues) as a function of the number of producing/consuming threads?

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  • Logic for rate approximation

    - by Rohan
    I am looking for some logic to solve the below problem. There are n transaction amounts : T1,T2,T3.. Tn. Commission for these transactions are calculated using a rate table provided as below. if amount between 0 and A1 - rate is r1 if amount between A1 and A2 - rate is r2 if amount between A2 and A1 - rate is r3 ... ... if amount greater than An - rate is r4 So if T1 < A1 then rate table returns r1 else if r1 < T1 < r2;it returns r2. So,lets says the rate table results for T1,T2 and T3 are r1,r2 and r3 respectively. Commission C = T1 * r1 + T2 * r2 + T3 * r3 e.g; if rate table is defined(rates are in %) 0 - 2500 - 1 2501 - 5000 - 2 5001 - 10000 - 4 10000 or more- 6 If T1 = 6000,T2 = 3000, T3 = 2000, then C= 6000 * 0.04 + 3000* 0.02 + 2000 * 0.01 = 320 Now my problem is whether we can approximate the commission amount if instead of individual values of T1,T2 and T3 we are provided with T1+T2+T3 (T) In the above example if T (11000) is applied to the rate tablewe would get 6% and which would result in a commision of 600. Is there a way to approximate the commission value given T instead of individual values of T1,T2,T3?

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  • which is better, creating a materialized view or a new table?

    - by Carson
    I have some demanding mysql queries that are needed to grap same up-to-date datasets from 5-7 mysql tables. I am thinking of creating a table or materialized view to gather all demanding columns from other tables, so as to increase performance. If I create that table, I may need to do extra insert / update / delete operation each time other tables updated. if I create materialized view, I am worrying if the performance can be greatly improved. Because data from other tables are changing very frequently. Most likely, the view may need to be created first everytime before selecting it. Any ideas? e.g. how to cache? other extra measures I can do?

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  • Matlab: Randomize and Split

    - by Null-Hypothesis
    I have following data matrix in Matlab, I am trying to actually split this into multiple segments by passing a variable to a matlab function. But before splitting I would like to shuffle the matrix. The size of my matrix is 150X4 s.data 5.1000 3.5000 1.4000 0.2000 4.9000 3.0000 1.4000 0.2000 4.7000 3.2000 1.3000 0.2000 4.6000 3.1000 1.5000 0.2000 5.0000 3.6000 1.4000 0.2000 .. s = data: [150x4 double] labels: [150x1 double] Coming from R environment I find MatLab is very strange. Initially I thought the columns in matrix has a relationshop like in a R dataframe but thats wrong in my assumption.

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  • Extension method return using generics

    - by Steven de Salas
    Is it possible to return a generic type using extension methods? For example, I have the following method: // Convenience method to obtain a field within a row (as a double type) public static double GetDouble(this DataRow row, string field) { if (row != null && row.Table.Columns.Contains(field)) { object value = row[field]; if (value != null && value != DBNull.Value) return Convert.ToDouble(value); } return 0; } This is currently used as follows: double value = row.GetDouble("tangible-equity"); but I would like to use the following code: double value = row.Get<double>("tangible-equity"); Is this possible and if so, what would the method look like?

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  • MySQL Removing Some Foreign keys

    - by Drew
    I have a table whose primary key is used in several other tables and has several foreign keys to other tables. CREATE TABLE location ( locationID INT NOT NULL AUTO_INCREMENT PRIMARY KEY ... ) ENGINE = InnoDB; CREATE TABLE assignment ( assignmentID INT NOT NULL AUTO_INCREMENT PRIMARY KEY, locationID INT NOT NULL, FOREIGN KEY locationIDX (locationID) REFERENCES location (locationID) ... ) ENGINE = InnoDB; CREATE TABLE assignmentStuff ( ... assignmentID INT NOT NULL, FOREIGN KEY assignmentIDX (assignmentID) REFERENCES assignment (assignmentID) ) ENGINE = InnoDB; The problem is that when I'm trying to drop one of the foreign key columns (ie locationIDX) it gives me an "ERROR 1025 (HY000): Error on rename" error. How can I drop the column in the assignment table above without getting this error?

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  • Fill data gaps - UNION, PARTITION BY, or JOIN?

    - by Dave Jarvis
    Problem There are data gaps that need to be filled. Would like to avoid UNION or PARTITION BY if possible. Query Statement The select statement reads as follows: SELECT count( r.incident_id ) AS incident_tally, r.severity_cd, r.incident_typ_cd FROM report_vw r GROUP BY r.severity_cd, r.incident_typ_cd ORDER BY r.severity_cd, r.incident_typ_cd Data Sources The severity codes and incident type codes are from: severity_vw incident_type_vw The columns are: incident_tally severity_cd incident_typ_cd Actual Result Data 36 0 ENVIRONMENT 1 1 DISASTER 27 1 ENVIRONMENT 4 2 SAFETY 1 3 SAFETY Required Result Data 36 0 ENVIRONMENT 0 0 DISASTER 0 0 SAFETY 27 1 ENVIRONMENT 0 1 DISASTER 0 1 SAFETY 0 2 ENVIRONMENT 0 2 DISASTER 4 2 SAFETY 0 3 ENVIRONMENT 0 3 DISASTER 1 3 SAFETY Question How would you use UNION, PARTITION BY, or LEFT JOIN to fill in the zero counts?

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  • Hibernate/JPA DB Schema Generation Best Practices

    - by Bytecode Ninja
    I just wanted to hear the opinion of Hibernate experts about DB schema generation best practices for Hibernate/JPA based projects. Especially: What strategy to use when the project has just started? Is it recommended to let Hibernate automatically generate the schema in this phase or is it better to create the database tables manually from earliest phases of the project? Pretending that throughout the project the schema was being generated using Hibernate, is it better to disable automatic schema generation and manually create the database schema just before the system is released into production? And after the system has been released into production, what is the best practice for maintaining the entity classes and the DB schema (e.g. adding/renaming/updating columns, renaming tables, etc.)? Thanks in advance.

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  • INSERT INTO statement that copies rows and auto-increments non-identity key ID column

    - by AmoebaMan17
    Given a table that has three columns ID (Primary Key, not-autoincrementing) GroupID SomeValue I am trying to write a single SQL INSERT INTO statement that will make a copy of every row that has one GroupID into a new GroupID. Example beginning table: ID | GroupID | SomeValue ------------------------ 1 | 1 | a 2 | 1 | b Goal after I run a simple INSERT INTO statement: ID | GroupID | SomeValue ------------------------ 1 | 1 | a 2 | 1 | b 3 | 2 | a 4 | 2 | b I thought I could do something like: INSERT INTO MyTable ( [ID] ,[GroupID] ,[SomeValue] ) ( SELECT (SELECT MAX(ID) + 1 FROM MyTable) ,@NewGroupID ,[SomeValue] FROM MyTable WHERE ID = @OriginalGroupID ) This causes a PrimaryKey violation since it will end up reusing the same Max(ID)+1 value multiple times as it seems. Is my only recourse to a bunch of INSERT statements in a T-SQL WHILE statement that has an incrementing Counter value? I also don't have the option of turning the ID into an auto-incrementing Identity column since that would breaking code I don't have source for.

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  • Please help, looking for any answer for long time :How to use SqlDataSource Control to work with Dro

    - by Shantanu Gupta
    I am trying to fetch a column value from a datasource when some value is selected from a dropdownlist on its change event. <asp:DropDownList ID="ddlCityName" runat="server" DataSourceID="dsCity" DataTextField="CityName" DataValueField="CityID" AutoPostBack="True" OnTextChanged="CityName_OnTextChanged"> </asp:DropDownList> <asp:SqlDataSource ID="dsCity" runat="server" ConnectionString="<%$ ConnectionStrings:GmapConnectionString %>" SelectCommand="SELECT * FROM [vcity]" ></asp:SqlDataSource> Here I want to fetch any other column's value that is not binded to a ddlCityName from sqldatasource. I have four columns in datasource i.e. name, id, address, phno. I want to fetch an address of a person who selects some value from ddl.

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  • How to get a column value contained in SqlDataSource to a variable.

    - by Shantanu Gupta
    I am trying to fetch a column value from a datasource when some value is selected from a dropdownlist on its change event. <asp:DropDownList ID="ddlCityName" runat="server" DataSourceID="dsCity" DataTextField="CityName" DataValueField="CityID" AutoPostBack="True" OnTextChanged="CityName_OnTextChanged"> </asp:DropDownList> <asp:SqlDataSource ID="dsCity" runat="server" ConnectionString="<%$ ConnectionStrings:GmapConnectionString %>" SelectCommand="SELECT * FROM [vcity]" ></asp:SqlDataSource> Here I want to fetch any other column's value that is not binded to a ddlCityName from sqldatasource. I have four columns in datasource i.e. name, id, address, phno. I want to fetch an address of a person who selects some value from ddl.

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  • Known problems with filemtime() on Windows - files getting touched arbitrarily?

    - by Pekka
    Is there a known issue leading to file modification times of cache files on Windows XP SP 3 getting arbitrarily updated, but without any actual change? Is there some service on a standard Windows XP - Backup, Sync, Versioning, Virus scanner - known to touch files? They all have a .txt extension. If there isn't, forget it. Then I'm getting something wrong in my cache routines, and I'll debug my way through. Background: I'm building a simple caching wrapper around a slow web site on a Windows server. I am comparing the filemtime() time stamp to some columns in the data base to determine whether a cached file is stale. I'm having problems using this method because the modification time of the cache files seems to get updated in between operations without me doing anything. THis results in stale files being displayed. I'm the only user on the machine. The operating system is Windows XP, the webserver a XAMPP Apache 2 with PHP 5.2

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  • MySQL - Selecting the top occurring entries

    - by RC
    Hi, Should be a simple one. Database is mydb. One of the columns is mydata. What SELECT query do I need in order to select the top 3 occurring results from mydata, but sorted alphabetically? For example, if my data is this: mydata ====== kilo (x 1 occurrence) lima (x 9 occurrences) golf (x 5 occurrences) echo (x 9 occurrences) zulu (x 8 occurrences) How do I get it to return "echo, lima, zulu", which are the top three frequently occurring entries sorted alphabetically? Thanks! EDIT: Just to add, they need to be distinct entries. Thanks!

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  • Adding relative week number column to MySQl results

    - by Anthony
    I have a table with 3 columns: user, value, and date. The main query returns the values for a specific user based on a date range: SELECT date, value FROM values WHERE user = '$user' AND date BETWEEN $start AND $end What I would like is for the results to also have a column indicating the week number relative to the date range. So if the date range is 1/1/2010 - 1/20/2010, then any results from the first Sun - Sat of that range are week 1, the next Sun - Sat are week 2, etc. If the date range starts on a Saturday, then only results from that one day would be week 1. If the date range starts on Thursday but the first result is on the following Monday, it would be week 2, and there are no week 1 results. Is this something fairly simple to add to the query? The only ideas I can come up with would be based on the week number for the year or the week number based on the results themselves (where in that second example above, the first result always gets week 1).

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  • DateTime in SqlServer VisualStudio C#

    - by menacheb
    Hi, I Have a DataBase in my project With Table named 'ProcessData' and columns named 'Start_At' (Type: DateTime) and 'End_At' (Type: DateTime) . When I try to enter a new record into this table, it enter the data in the following format: 'YYYY/MM/DD HH:mm', when I actualy want it to be in that format: 'YYYY/MM/DD HH:mm:ss' (the secondes dosen't apper). Does anyone know why, and what should I do in order to fix this? Here is the code I using: con = new SqlConnection("...."); String startAt = "20100413 11:05:28"; String endAt = "20100414 11:05:28"; ... con.Open();//open the connection, in order to get access to the database SqlCommand command = new SqlCommand("insert into ProcessData (Start_At, End_At) values('" + startAt + "','" + endAt + "')", con); command.ExecuteNonQuery();//execute the 'insert' query. con.Close(); Many thanks

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  • Detecting regional settings (List Separator) from web

    - by Toms Mikoss
    After having the unpleasant surprise that Comma Seperated Value (CSV) files are not necessarily comma-separated, I'm trying to find out if there is any way to detect what the regional settings list separator value is on the client machine from http request. Scenario is as follows: A user can download some data in CSV format from web site (RoR, if it matters). That CSV file is generated on the fly, sent to the user, and most of the time double-clicked and opened in MS Excel on Windows machine at the destination. Now, if the user has ',' set as the list separator, the data is properly arranged in columns, but if any other separator (';' is widely used here) is set, it all just gets thrown into a single column. So, is there any way to detect what separator is used on the client machine, and generate the file accordingly? I have a sinking feeling that it is not, but I'd like to be sure before I pass the 'can't be done, sorry' line to the customer :)

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  • search for a string , and add if it matches

    - by Sharat Chandra
    I have a file that has 2 columns as given below.... 101 6 102 23 103 45 109 36 101 42 108 21 102 24 109 67 and so on...... I want to write a script that adds the values from 2nd column if their corresponding first column matches for example add all 2nd column values if it's 1st column is 101 add all 2nd column values if it's 1st colummn is 102 add all 2nd column values if it's 1st colummn is 103 and so on ... i wrote my script like this , but i'm not getting the correct result awk '{print $1}' data.txt > col1.txt while read line do awk ' if [$1 == $line] sum+=$2; END {print "Sum for time stamp", $line"=", sum}; sum=0' data.txt done < col1.txt

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