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• performance of parameterized queries for different db's

  - by tuinstoel

  A lot of people know that it is important to use parameterized queries to prevent sql injection attacks. Parameterized queries are also much faster in sqlite and oracle when doing online transaction processing because the query optimizer doesn't have to reparse every parameterized sql statement before executing. I've seen sqlite becoming 3 times faster when you use parameterized queries, oracle can become 10 times faster when you use parameterized queries in some extreme cases with a lot of concurrency. How about other db's like mysql, ms sql, db2 and postgresql? Is there an equal difference in performance between parameterized queries and literal queries?

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• function binding and the clone() function - Jquery

  - by Sam Vloeberghs

  Hi I have problems with my keyup binding when cloning an element. Here's the scenario: I have an html markup like this: <tr class="rijbasis"> <td> <input type="text" class="count" /> </td> <td> <span class="cost">10</span> </td> <td> <span class="total">10</span> </td> </tr> I'm binding an keyup function to the input element of my table row like this: $('.rijbasis input').keyup(function(){ var parent = $(this).parent().parent(); $('.total',parent).text(parseInt($('.cost',parent).text()) * parseInt($('.count',parent).val())); } I designed the function like this so I could clone the table row on a onclick event and append it to the tbody: $('.lineadd').click(function(){ $('.contract tbody').append($('.contract tbody tr:last').clone()); $('.contract tbody tr:last input').val("0"); }); This al works , but the keyup function doesnt work on the input elements of the cloned row.. Can anybody help or advice? I hope I was clear enough and I'll be surely adding details if needed to solve this problem. Greetings

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• Object reference not set to an instance of an object.

  - by Lambo

  I have the following code - private static void convert() { string csv = File.ReadAllText("test.csv"); string year = "2008"; XDocument doc = ConvertCsvToXML(csv, new[] { "," }); doc.Save("update.xml"); XmlTextReader reader = new XmlTextReader("update.xml"); XmlDocument testDoc = new XmlDocument(); testDoc.Load(@"update.xml"); XDocument turnip = XDocument.Load("update.xml"); webservice.singleSummary[] test = new webservice.singleSummary[1]; webservice.FinanceFeed CallWebService = new webservice.FinanceFeed(); foreach(XElement el in turnip.Descendants("row")) { test[0].account = el.Descendants("var").Where(x => (string)x.Attribute("name") == "account").SingleOrDefault().Attribute("value").Value; test[0].actual = System.Convert.ToInt32(el.Descendants("var").Where(x => (string)x.Attribute("name") == "actual").SingleOrDefault().Attribute("value").Value); test[0].commitment = System.Convert.ToInt32(el.Descendants("var").Where(x => (string)x.Attribute("name") == "commitment").SingleOrDefault().Attribute("value").Value); test[0].costCentre = el.Descendants("var").Where(x => (string)x.Attribute("name") == "costCentre").SingleOrDefault().Attribute("value").Value; test[0].internalCostCentre = el.Descendants("var").Where(x => (string)x.Attribute("name") == "internalCostCentre").SingleOrDefault().Attribute("value").Value; MessageBox.Show(test[0].account, "Account"); MessageBox.Show(System.Convert.ToString(test[0].actual), "Actual"); MessageBox.Show(System.Convert.ToString(test[0].commitment), "Commitment"); MessageBox.Show(test[0].costCentre, "Cost Centre"); MessageBox.Show(test[0].internalCostCentre, "Internal Cost Centre"); CallWebService.updateFeedStatus(test, year); } It is coming up with the error of - NullReferenceException was unhandled, saying that the object reference not set to an instance of an object. The error occurs on the first line test[0].account. How can I get past this?

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• How to write a Compiler in C for C

  - by Kerb_z

  I want to write a Compiler for C. This is a Project for my College i am doing as per my University. I am an intermediate programmer in C, with understanding of Data Structures. Now i know a Compiler has the following parts: 1. Lexer 2. Parser 3. Intermediate Code Generator 4. Optimizer 5. Code Generator I want to begin with the Lexer part and move on to Parser. I am consulting the following book: Compilers: Principles, Techniques, and Tools by Alfred V. Aho, Ravi Sethi, Jeffrey D. Ullman. The thing is that this book is highly theoretical and perplexing to me. I really appreciate the authors. But the point is i am not able to begin my project, as if i am blinded where to go. Need guidance please help.

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• Rails: creating a custom data type, to use with generator classes and a bunch of questions related t

  - by Shyam

  Hi, After being productive with Rails for some weeks, I learned some tricks and got some experience with the framework. About 10 days ago, I figured out it is possible to build a custom data type for migrations by adding some code in the Table definition. Also, after learning a bit about floating points (and how evil they are) vs integers, the money gem and other possible solutions, I decided I didn't WANT to use the money gem, but instead try to learn more about programming and finding a solution myself. Some suggestions said that I should be using integers, one for the whole numbers and one for the cents. When playing in script/console, I discovered how easy it is to work with calculations and arrays. But, I am talking to much (and the reason I am, is to give some sufficient background). Right now, while playing with the scaffold generator (yes, I use it, because I like they way I can quickly set up a prototype while I am still researching my objectives), I like to use a DRY method. In my opinion, I should build a custom "object", that can hold two variables (Fixnum), one for the whole, one for the cents. In my big dream, I would be able to do the following: script/generate scaffold Cake name:string description:text cost:mycustom Where mycustom should create two integer columns (one for wholes, one for cents). Right now I could do this by doing: script/generate scaffold Cake name:string description:text cost_w:integer cost_c:integer I had also had an idea that would be creating a "cost model", which would hold two columns of integers and create a cost_id column to my scaffold. But wouldn't that be an extra table that would cause some kind of performance penalty? And wouldn't that be defy the purpose of the Cake model in the first place, because the costs are an attribute of individual Cake entries? The reason why I would want to have such a functionality because I am thinking of having multiple "costs" inside my rails application. Thank you for your feedback, comments and answers! I hope my message got through as understandable, my apologies for incorrect grammar or weird sentences as English is not my native language.

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• How do I use price data in one table for a calculation that is stored in another table?

  - by shane

  I'm still leanring PHP/MySQL but have learned quite a bit thanks to codies on StackOverflow. I'm trying to setup a sort of room reservations system using two tables: SETUP: Room price table: Has, prices for a type room a client may want to rent as well as the dates (day of week) they wish to use it. Pricing varies based on day of the week and per room. I've setup a different table for each room type as each room type carries different pricing for each day of the week. So, There is an Alpha room table, Bravo room, etc. Within Alpha table are headers for the days of the week with pricing pre-entered into the rows. Client info table: Has the name, address, date of room use, etc data for the specific client. EXAMPLE: Alpha-room price table: Sun = $100; Mon = $200; Tue=$300 and so on. Bravo-room price table: Sun = $100; Mon = $200; Tue=$300 and so on. Client data table: ClientName; date-of-room-use; address; day_subtotal; grand_total. QUESTION: I'm trying to find PHP code that will: look at the date of room use in the client data table, look up the associated cost for that date in the specific room pricing table, record that unit cost in the day subtotal of the client data table and sum a grand total in the grand total row of the client data table (assuming the room may be used more than one day by the customer). I know there's something to do with join but I'm finding it difficult to grasp the concept and, if someone can demonstrate using this example, I think I will have a better understanding of how to work this sort of transaction. Thank you ALL in advance for your suggestions or alternatvie approaches.

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• Reuse select query in a procedure in Oracle

  - by Jer

  How would I store the result of a select statement so I can reuse the results with an in clause for other queries? Here's some pseudo code: declare ids <type?>; begin ids := select id from table_with_ids; select * from table1 where id in (ids); select * from table2 where id in (ids); end; ... or will the optimizer do this for me if I simply put the sub-query in both select statements?

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• Creating a function in Postgresql that does not return composite values

  - by celenius

  I'm learning how to write functions in Postgresql. I've defined a function called _tmp_myfunction() which takes in an id and returns a table (I also define a table object type called _tmp_mytable) -- create object type to be returned CREATE TYPE _tmp_mytable AS ( id integer, cost double precision ); -- create function which returns query CREATE OR REPLACE FUNCTION _tmp_myfunction( id integer ) RETURNS SETOF _tmp_mytable AS $$ BEGIN RETURN QUERY SELECT id, cost FROM sales WHERE id = sales.id; END; $$ LANGUAGE plpgsql; This works fine when I use one id and call it using the following approach: SELECT * FROM _tmp_myfunction(402); What I would like to be able to do is to call it, but to use a column of values instead of just one value. However, if I use the following approach I end up with all values of the table in one column, separated by commas: -- call function using all values in a column SELECT _tmp_myfunction(t.id) FROM transactions as t; I understand that I can get the same result if I use SELECT _tmp_myfunction(402); instead of SELECT * FROM _tmp_myfunction(402); but I don't know how to construct my query in such a way that I can separate out the results.

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• How to find an embedded platform?

  - by gmagana

  I am new to the locating hardware side of embedded programming and so after being completely overwhelmed with all the choices out there (pc104, custom boards, a zillion option for each board, volume discounts, devel kits, ahhh!!) I am asking here for some direction. Basically, I must find a new motherboard and (most likely) re-implement the program logic. Rewriting this in C/C++/Java/C#/Pascal/BASIC is not a problem for me. so my real problem is finding the hardware. This motherboard will have several other devices attached to it. Here is a summary of what I need to do: Required: 2 RS232 serial ports (one used all the time for primary UI, the second one not continuous) 1 modem (9600+ baud ok) [Modem will be in simultaneous use with only one of the serial port devices, so interrupt sharing with one serial port is OK, but not both] Minimum permanent/long term storage: Whatever O/S requires + 1 MB (executable) + 512 KB (Data files) RAM: Minimal, whatever the O/S requires plus maybe 1MB for executable. Nice to have: USB port(s) Ethernet network port Wireless network Implementation languages (any O/S I will adapt to): First choice Java/C# (Mono ok) Second choice is C/Pascal Third is BASIC Ok, given all this, I am having a lot of trouble finding hardware that will support this that is low in cost. Every manufacturer site I visit has a lot of options, and it's difficult to see if their offering will even satisfy my must-have requirements (for example they sometimes list 3 "serial ports", but it appears that only one of the three is RS232, for example, and don't mention what the other two are). The #1 constraint is cost, #2 is size. Can anyone help me with this? This little task has left me thinking I should have gone for EE and not CS :-). EDIT: A bit of background: This is a system currently in production, but the original programmer passed away, and the current hardware manufacturer cannot find hardware to run the (currently) DOS system, so I need to reimplement this in a modern platform. I can only change the programming and the motherboard hardware.

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• Using "CASE" in Where clause to choose various column harm the performance

  - by zivgabo

  I have query which needs to be dynamic on some of the columns, meaning I get a parameter and according its value I decide which column to fetch in my Where clause. I've implemented this request using "CASE" expression: (CASE @isArrivalTime WHEN 1 THEN ArrivalTime ELSE PickedupTime END) >= DATEADD(mi, -@TZOffsetInMins, @sTime) AND (CASE @isArrivalTime WHEN 1 THEN ArrivalTime ELSE PickedupTime END) < DATEADD(mi, -@TZOffsetInMins, @fTime) If @isArrivalTime = 1 then chose ArrivalTime column else chose PickedupTime column. I have a clustered index on ArrivalTime and nonclustered index on PickedupTime. I've noticed that when I'm using this query (with @isArrivalTime = 1), my performance is a lot worse comparing to only using ArrivalTime. Maybe the query optimizer can't use\choose the index properly in this way? I compared the execution plans an noticed that when I'm using the CASE 32% of the time is being wasted on the index scan, but when I didn't use the CASE(just usedArrivalTime`) only 3% were wasted on this index scan. Anyone know the reason for this?

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• Oracle (Old?) Joins - A tool/script for conversion?

  - by Grasper

  I have been porting oracle selects, and I have been running across a lot of queries like so: SELECT e.last_name, d.department_name FROM employees e, departments d WHERE e.department_id(+) = d.department_id; ...and: SELECT last_name, d.department_id FROM employees e, departments d WHERE e.department_id = d.department_id(+); Are there any guides/tutorials for converting all of the variants of the (+) syntax? What is that syntax even called (so I can scour google)? Even better.. Is there a tool/script that will do this conversion for me (Preferred Free)? An optimizer of some sort? I have around 500 of these queries to port.. When was this standard phased out? Any info is appreciated.

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• Python: Does one of these examples waste more memory?

  - by orokusaki

  In a Django view function which uses manual transaction committing, I have: context = RequestContext(request, data) transaction.commit() return render_to_response('basic.html', data, context) # Returns a Django ``HttpResponse`` object which is similar to a dictionary. I think it is a better idea to do this: context = RequestContext(request, data) response = render_to_response('basic.html', data, context) transaction.commit() return response If the page isn't rendered correctly in the second version, the transaction is rolled back. This seems like the logical way of doing it albeit there won't likely be many exceptions at that point in the function when the application is in production. But... I fear that this might cost more and this will be replete through a number of functions since the application is heavy with custom transaction handling, so now is the time to figure out. If the HttpResponse instance is in memory already (at the point of render_to_response()), then what does another reference cost? When the function ends, doesn't the reference (response variable) go away so that when Django is done converting the HttpResponse into a string for output Python can immediately garbage collect it? Is there any reason I would want to use the first version (other than "It's 1 less line of code.")?

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• c++ exercise question

  - by Djecua

  in need of help on a C++ program that will help a deli owner help her customers.Prompt the user for the number of bagels.if then calculate the customers payment two ways. first it finds the price of the smallest multiple of 13 bagels that is closet to the customer's order. it then calculates the price of the customer's order so that the customer's payment is the smallest amount possible with the customer getting the exact number of bagels ordered. if the first method is the smallest amount the program outputs the number of bagels the customer will receive along with the dollar amount owed and the dollar amount saved. otherwise just print the number of bagels received the dollar amount owed $ 3.80 for a dozen bagels (13 bagels) half a dozen(6 bagels) sing bagel cost $.50 owner of the deli is a honest merchant, customers always get the best price on an order, even if they get more bagels than ordered, for example a customer that orders 10 bagels would pay $ 4.60 (2.60 for a half dozen bagels plus $2.00 for 4 single bagels.merchant gives her customer 13 bagels saving the customer $0.80 If someone can example to me how would i design to give customer extra bagels and how to calculate cost.

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• wordpress php > div issue

  - by Philip Bateman

  Thanks in advance for you help Ive been doing this as a lovejob for friends and now im getting quotes of several hundred dollars for minor homepage variation and I'm not sure if its valid. I'm not a programmer myself, just trying hard :) Via the CafePress press75 theme, I'm trying to go from 1 / 2 / 3 column home layout, to 1-2 merged and 3, push the 2nd column data to the right and have the 1st column span as a 16:9 gallery (nextgengallery plugin installed). Is this really a complex thing from a coding perspective? The current guy talking to me is saying its going to cost $700 or 800 AUD to alter, which is rough when the template cost $85.. From this http://shocolate.com.au.previewdns.com/wp-content/uploads/2010/05/shocolatecurrent.jpg to this 'url+Shocolatelooklikethis.jpg' I was able to get the sidebar removed by taking out ‘‘ near the bottom of home.css.. Just can’t get the middle data to flow over it? This would be ideal as a result, as the system puts the latest selected blog post on the homepage, so if we can get rid of the sidebar div and have the text appear where it was, that would be ideal. Removing the sidebar from the bottom of home.php and setting the thumbnail width to say 450 gives me the result im after EXCEPT the text doesn’t fill where the sidebar is, it wraps underneath. Reference 'shocolate.com.au.previewdns.com' for current site Thank you!!! Phil (Melbourne)

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• Perl, strings, floats, unit testing and regexps!

  - by Chris R

  OK, as a preface this question potentially is 'stupider' than my normal level of question - however this problem has been annoying me for the last few days so I'll ask it anyway. I'll give a mock example of what my problem is so I can hope to generalize it to my current problem. #!/usr/bin/perl -w use strict; use Test::More 'no_plan'; my $fruit_string = 'Apples cost $1.50'; my ($fruit, $price) = $fruit_string =~ /(\w+)s cost \$(\d+\.\d+)/; # $price += 0; # Uncomment for Great Success is ($price, 1.50, 'Great Success'); Now when this is run I get the message # Failed test 'Great Success' # got: '1.50' # expected: '1.5' To make the test work - I either uncomment the commented line, or use is ($price, '1.50', 'Great Success'). Both options do not work for me - I'm testing a huge amount of nested data using Test::Deep and cmp_deeply. My question is, how can you extract a double from a regexp then use it immediately as a double - or if there is a better way altogether let me know - and feel free to tell me to take up gardening or something lol, learning Perl is hard.

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• Will unused deconstructors be optimized out?

  - by Brendan Long

  Assuming MyClass uses the default deconstructor (or no deconstructor), and this code: MyClass buffer[] = new MyClass[i]; // Construct N objects using placement new for(size_t i = 0; i < N; i++){ ~buffer[i]; } delete[] buffer; Is there any optimizer that would be able to remove this loop? Also, is there any way for my code to detect if MyClass is using an empty/default constructor?

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• Which is the best license for my Open Source project?

  - by coderex

  I am a web developer, and I don't have enough knowledge about software licenses. I wish to publish some of my works, and I need to select licenses for them. My software product is free of cost. But I have some restrictions on the distribution/modification of the code. It's free of cost (but donations are acceptable ;-)). The source code is freely available. You can use, customize or edit/remove code (as long as the basic nature of the software is not changed). You don't have any permission to change the product name. There are some libraries and classes which are in a folder caller "myname". You don't have the permission to rename "myname". You can contribute any additions or modifications to my project, to the original source repository (the contributors name/email/site link will be listed on the credit file). You can't remove the original author's name from the license. You can put the license file or license code anywhere in the project file or folder. You can redistribute this code as free or commercial software. :) Do you think all these restrictions are valid? Given these restrictions, which license should I use? Edit 1:- My main intention is to make the product more popular with free source code while ensuring the original author is not ignored. The product is open. Edit 2:- Thank you all, the above points are because of my lack of knowledge of license terms. You can help me to correct or remove some of the above points. What I'm basically looking for is in my Edit 1.

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• Exporting and reformatting data out of MS Excel

  - by Matt H

  I have a huge Excel spreadsheet containing telephone calling rates to a number of different countries. The format of the columns is: Country, RateLocality, Prefixes, Rate, Wholesale e.g. Afganistan, Default, 93;930;931;9321;9322;9323;9324;9325;9326;9327;9328;9329;9331;9332;9333;9334;9335;9336;9337;9338;9339;9341;9342;9343;9344;9345;9346;9347;9348;9349;9351;9352;9353;9354;9355;9356;9357;9358;9359;9361;9362;9363;9364;9365;9366;9367;9368;9369;9371;9372;9373;9374;9376;938;939; $ 1.023, $0.455 These rates change every so often and I need to get them into another system that can import them using CSV. The eventual format is: LD PREPEND CODE ie. 00 or 011,CountryCode,Area Code,Comment,Connect Cost,Included Seconds,Per Minute Cost,Pricelist,Increment So to convert that above line I'd have 00,"Afganistan",93,"Default",1.023,60,1.023,10 00,"Afganistan",931,"Default",1.023,60,1.023,10 ... 00,"Afganistan",939,"Default",1.023,60,1.023,10 Where 00, 60 and 10 are hard coded and merged with the other data from excel. How can I export this data into the required format given that I need to reformat it as it goes. Should I export to XML and use XSLT or some other process to massage the data into CSV? If that is the case, how do I do it simply and quickly.

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• Progressive enhancement of anchor tags to avoid onclick="return false;"

  - by Chris Beck

  Unobtrusive JS suggests that we don't have any onclick attributes in our HTML templates. <a href="/controller/foo/1">View Foo 1</a> A most basic progressive enhancement is to convert an that anchor tag to use XHR to retrieve a DOM fragment. So, I write JS to add an event listener for a."click" then make an XHR to a.href. Alas, the browser still wants to navigate to "/controller/foo". So, I write JS to dynamically inject a.onclick = "return false;". Still unobtrusive (I guess), but now I'm paying the the cost of an extra event handler. To avoid the cost of 2 event listeners, I could shove my function call into the onclick attribute <a href="/controller/foo/1" onclick="myXHRFcn(); return false;"> But that's grodo for all sorts of reasons. To make it more interesting, I might have 100 anchor tags that I want to enhance. A better pattern is a single listener on a parent node that relies on event bubbling. That's cool, but how do I short circuit the browser from navigating to the URL without this on every anchor node? onclick="return false;" Manipulating the href is not an option. It must stay intact so the context menu options to copy or open in new page work as expected.

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• Which is the best license for Open Source project?

  - by coderex

  Hi friends, I am a web developer, and i don't have enough knowledge in software licenses. I wish to publish some of my works. and i need to apply a licenses for that. My software/product is free of cost. But I have some restrictions on the distribution/Modification. Its free of cost.(but donations are acceptable ;-)) Source Code is freely available; that you can use, customize or edit/remove(but don't deviate the basic nature of the software). You don't have any permission to change the product name. There are some lib or class are and which is put into a folder caller "myname", you don't have the permission to rename "myname". You can contribute any additions modifications to my project, to the original source repository. (The contributors name/email/site link will be listed on the credit file). Don't remove the original author's name from the license. Put the license file or license code any where is in the project file or folder. You can redistribute this code as free or commercial. :) What you this, all these kinda restrictions are valid or ... ? For this, which license i want to use.

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• What is the fastest way to insert 100 000 records from one database to another?

  - by Pentium10

  I have a mobile application. My client has a large data set ~100.000 records. It's updated frequently. When we sync we need to copy from one database to another. I have attached the second database to the main, and run an insert into table select * from sync.table. This is extremely slow, it takes about 10 minutes I think. I noticed that the journal file gets increased step by step. How can I speed this up? EDITED 1 I have indexes off, and I have journal off. Using insert into table select * from sync.table it still takes 10 minutes. EDITED 2 If I run a query like select id,invitem,invid,cost from inventory where itemtype = 1 order by invitem limit 50 it takes 15-20 seconds. The table schema is: CREATE TABLE inventory ('id' INTEGER PRIMARY KEY AUTOINCREMENT NOT NULL, 'serverid' INTEGER NOT NULL DEFAULT 0, 'itemtype' INTEGER NOT NULL DEFAULT 0, 'invitem' VARCHAR, 'instock' FLOAT NOT NULL DEFAULT 0, 'cost' FLOAT NOT NULL DEFAULT 0, 'invid' VARCHAR, 'categoryid' INTEGER DEFAULT 0, 'pdacategoryid' INTEGER DEFAULT 0, 'notes' VARCHAR, 'threshold' INTEGER NOT NULL DEFAULT 0, 'ordered' INTEGER NOT NULL DEFAULT 0, 'supplier' VARCHAR, 'markup' FLOAT NOT NULL DEFAULT 0, 'taxfree' INTEGER NOT NULL DEFAULT 0, 'dirty' INTEGER NOT NULL DEFAULT 1, 'username' VARCHAR, 'version' INTEGER NOT NULL DEFAULT 15 ) Indexes are created like CREATE INDEX idx_inventory_categoryid ON inventory (pdacategoryid); CREATE INDEX idx_inventory_invitem ON inventory (invitem); CREATE INDEX idx_inventory_itemtype ON inventory (itemtype); I am wondering, the insert into ... select * from isn't the fastest built-in way to do massive data copy? EDITED 3 SQLite is serverless, so please stop voting a particular answer, because that is not the answer I'm sure.

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• passing xml to a webservice

  - by Neale

  I have a simple web service that will have one method: DoTransactions(xlm) Now the reason that i am using XML as a parameter is due to the fact that the parameters will often change. So for example it could be: <payload> <userId>1234</userid> <partnerId>ptn654</partnerId> </payload> OR <payload> <partnerId>ptn654</partnerId> <items> <item1> <cost>10</cost> <description>This is item 1</description> </item1> </items> </payload> As you can see the XML string will always change (this is due to a client request) Would it be better to rather pass in a string and parse the XML in the method or should is there a better way to do it. This web service will be used for varios different code languages.

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• Oracle Query Optimization: Why is My Second Query Faster?

  - by Patrick Cuff

  I was having some performance issues with an Oracle query, so I downloaded a trial of the Quest SQL Optimizer for Oracle, which made some changes that dramatically improved the query's performance. I'm not exactly sure why the recommended query had such an improvement; can anyone provide an explanation? Before: SELECT t1.version_id, t1.id, t2.field1, t3.person_id, t2.id FROM table1 t1, table2 t2, table3 t3 WHERE t1.id = t2.id AND t1.version_id = t2.version_id AND t2.id = 123 AND t1.version_id = t3.version_id AND t1.VERSION_NAME <> 'AA' order by t1.id Plan Cost: 831 Elapsed Time: 00:00:21.40 Number of Records: 40,717 After: SELECT /*+ USE_NL_WITH_INDEX(t1) */ t1.version_id, t1.id, t2.field1, t3.person_id, t2.id FROM table2 t2, table3 t3, table1 t1 WHERE t1.id = t2.id + 0 AND t1.version_id = t2.version_id + 0 AND t2.id = 123 AND t1.version_id = t3.version_id + 0 AND t1.VERSION_NAME || '' <> 'AA' AND t3.version_id = t2.version_id + 0 order by t1.id Plan Cost: 686 Elapsed Time: 00:00:00.95 Number of Records: 40,717 Questions: Why does re-arranging the order of the tables in the FROM clause help? Why does adding + 0 to the WHERE clause comparisons help? Why does || '' <> 'AA' in the WHERE clause VERSION_NAME comparison help? Is this a more efficient way of handling possible nulls on this column?

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• Windows Phone 8 xaml textblock binding format

  - by user2042227

  I would like to format a textblock which is binded to a value, to show "R" before the actuall value, is this possible, cause I cannot directly change the value? Thank you <ListBox x:Name="lstbundleListbox" Foreground="White" Height="320" HorizontalAlignment="Center"> <ListBox.ItemContainerStyle> <Style TargetType="ListBoxItem"> <Setter Property="HorizontalContentAlignment" Value="Center" /> </Style> </ListBox.ItemContainerStyle> <ListBox.ItemTemplate> <DataTemplate> <StackPanel> <TextBlock Text="{Binding name}" TextWrapping="Wrap" HorizontalAlignment="Center"/> <TextBlock Text="{Binding cost}" TextWrapping="Wrap" HorizontalAlignment="Center"/> </StackPanel> </DataTemplate> </ListBox.ItemTemplate> <ItemsControl.ItemsPanel> <ItemsPanelTemplate> <StackPanel Orientation="Vertical"/> </ItemsPanelTemplate> </ItemsControl.ItemsPanel> </ListBox> So I basically want the texblock to show R(cost)

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• How do I compare 2 fields and return the lowest value of each record?

  - by BigRob

  I'm slowly learning access to make a database of products and suppliers for my parents' business. What i've got is a table of products indexed by our product reference and 2 more tables for 2 different suppliers that contains the suppliers product reference and price that links with our reference. I've made a query that performs a left outer join such that it returns a table of our products with each supplier's reference and price, i.e: Ref | Product Name | Supplier 1 Ref | Supplier 1 Price | Supplier 2 Ref | Supplier 2 Price Here's the query I used: SELECT Catalog.Ref, Catalog.[Product Name], Catalog.Price, [D Products].[Supplier Ref], [D Products].Cost, [GS Products].[Supplier Ref], [GS Products].Cost FROM ([Catalog] LEFT JOIN [D Products] ON Catalog.Ref = [D Products].Ref) LEFT JOIN [GS Products] ON Catalog.Ref = [GS Products].Ref; Not all products are available from both suppliers, hence the outer join. What I want to do (with a query?) is to take the table produced by the query above and simply show the product reference, cheapest supplier reference and cheapest supplier price, i.e: Ref | Cheapest Suppplier Ref | Cheapest Supplier Price Unfortunately my SQL knowledge isn't quite good enough to figure this out, but if anyone can help i'd really appreciate it. Thanks, Rob

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