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  • Count The Amount Of Data In An Array Including SOME Null

    - by Josephine
    I'm coding in java and I need to create a function that returns the number of Data objects that are currently in an ArrayList. At the moment I have this: int count = 0; for (int i = 0; i < data.length; i++) { if (data[i] != null) { count ++; } } return count; But the problem is that an array list that includes null data is acceptable, and I have to count their null data towards this counter. How do I include the null data that's in the middle of this array, and not the null data that's not supposed to be counted for? For example, I have some tester code that adds (8),null,null,(23),(25) to the array, and this function should return 5 when the initial array size is 10. Thank you so much

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  • Quick note from JavaOne … check my twitter feed

    - by terrencebarr
    Just a quick note from JavaOne … excellent response to Oracle’s embedded Java announcements and strategy. Our DEMOGround booth is always busy – people want to learn more about Oracle Java ME Embedded 3.2, see it in action. Today’s keynote for the Java Embedded @ JavaOne sub conference was excellent – full house, great line up of partners and content. Haven’t had time to blog, but been tweeting about the latest news around embedded Java – be sure to monitor @terrencebarr. And check my last blog for embedded Java highlights. Oh, and check this latest summary on blogs.oracle.com “Huge Opportunity in Small Things” Cheers, – Terrence Filed under: Mobile & Embedded Tagged: "Oracle Java ME Embedded", embedded, Embedded Java, Java Embedded @ JavaOne, JavaOne

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  • Ubuntu 12.04 64 bit doesn't work on a win7 with check point full disk encryption

    - by Victor Rodriguez
    I installed Ubuntu 12.04 64 bit with the Wubi installer on a Windows 7 with Check Point Full Disk Encryption. The Wubi Installer runs without any trouble selecting the compatibility mode with WinXP and as Administrator. The problem is that after the installation is complete and the reboot done, when you restart the system, there's no option to start Ubuntu instead of Windows. I recently installed Ubuntu on other Win7 machines without any problem. But those laptops don't have the Check Point Full Disk Encryption. And when you restart the system you have the option to start in Ubuntu. If somebody has resolved this issue please share...!!! Regards! Víctor

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  • Tor check failed though Vidalia shows green onion

    - by Wolter Hellmund
    I have installed tor successfully and Vidalia shows it is running without problems; however, when I check if I am using tor in this website I get an error message saying I am not using tor. I have tried two things to fix this: I installed ProxySwitchy on Google Chrome, and created a profile for Tor (with address 127.0.0.1, port 8118), but enabling the proxy doesn't change the results in the tor check website linked before. I changed my network proxy settings through System Settings Network from None to Manual, and selected as address always 127.0.0.1 and as port 8118 for all but for the socket, for which I entered 9050 instead. This makes internet stop working completely. How can I fix this problem?

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  • SQL SERVER – Check If Column Exists in SQL Server Table

    - by Pinal Dave
    A very frequent task among SQL developers is to check if any specific column exists in the database table or not. Based on the output developers perform various tasks. Here are couple of simple tricks which you can use to check if column exists in your database table or not. Method 1 IF EXISTS(SELECT * FROM sys.columns WHERE Name = N'columnName' AND OBJECT_ID = OBJECT_ID(N'tableName')) BEGIN PRINT 'Your Column Exists' END   For AdventureWorks sample database IF EXISTS(SELECT * FROM sys.columns WHERE Name = N'Name' AND OBJECT_ID = OBJECT_ID(N'[HumanResources].[Department]')) BEGIN PRINT 'Your Column Exists' END   Method 2 IF COL_LENGTH('table_name','column_name') IS NOT NULL BEGIN PRINT 'Your Column Exists' END For AdventureWorks sample database IF COL_LENGTH('[HumanResources].[Department]','Name') IS NOT NULL BEGIN PRINT 'Your Column Exists' END Method 3 IF EXISTS( SELECT TOP 1 * FROM INFORMATION_SCHEMA.COLUMNS WHERE [TABLE_NAME] = 'TableName' AND [COLUMN_NAME] = 'ColumnName' AND [TABLE_SCHEMA] = 'SchemaName') BEGIN PRINT 'Your Column Exists' END For AdventureWorks sample database IF EXISTS( SELECT TOP 1 * FROM INFORMATION_SCHEMA.COLUMNS WHERE [TABLE_NAME] = 'Department' AND [COLUMN_NAME] = 'Name' AND [TABLE_SCHEMA] = 'HumanResources') BEGIN PRINT 'Your Column Exists' END Let me know if you know any other method to find if Column Exists in SQL Server Table. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • How To: Spell Check InfoPath web form in SharePoint

    - by JeremyRamos
    This post is a compiled version of Steve Cavanagh's blog post on How To: Spell Check an InfoPath form displayed via XmlFormView. Many are not able to follow Steve's instructions due to lack of details. See below a downloadable zip of all changes need installed for your InfoPath Spell Checker. File Contents: CustomSpellCheckEntirePage.js - This is a customized SpellCheckEntirePage.js which includes changes outlined in Steve's post above.   FormServer.aspx - Note that this will replace the exisitng FormServer.aspx - this file acts like a masterpage for all infopath forms. So this change will add the spellchecker to all infopath forms in the sharepoint farm. Only thing i changed here is to add the 'Spell Check' link before and after the form.   ReadMe.rtf - Contains instructions where to copy the files to in your MOSS WFE server.

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  • Keeping Entitlements in Check

    - by Naresh Persaud
    Thanks for going the webcast on keeping entitlements in check. As a follow up, I have attached the slides to the webcast. The webcast will be available on demand shortly via IOUG.   A few key takeaways: Application security means applying both preventive and detective controls. Audit and security groups need the combination of both access certification and runtime dynamic authorization. Today, security policy is largely fragmented and brittle to change. The result is audit exposure for highly regulated applications.  By addressing the entire value chain of application security with a comprehensive platform approach, organizations can reduce the risk and improve compliance.    Ioug webcast entitlements in check View more PowerPoint from OracleIDM

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  • Check for Instant File Initialization

    - by TiborKaraszi
    Instant File initialization, IFI, is generally a good thing to have. Check out this earlier blog post of mine f you don't know what IFI is and why it is a good thing: blog . The purpose of this blog post is to provide a simple script you can use to check if you have IFI turned on. Note that the script below uses undocumented commands, and might take a while if you have a large errorlog file... USE MASTER ; SET NOCOUNT ON -- *** WARNING: Undocumented commands used in this script !!! *** -- --Exit...(read more)

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  • MySql, InnoDB & Null Values

    - by pws5068
    Formerly I was using MyISAM storage engine for MySql and I had defined the combination of three fields to be unique. Now I have switched to InnoDB, which I assume caused this problem, and now NULL != NULL. So for the following table: ID (Auto) | Field_A | Field_B | Field_C I can insert (Field_A,Field_B,Field_C) Values(1,2,NULL) (1,2,NULL) (1,2,NULL) infinitely many times. How can I prevent this behavior?

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  • What is the Null Character literal in TSQL?

    - by David in Dakota
    I am wondering what the literal for a Null character (e.g. '\0') is in TSQL. Note: not a NULL field value, but the null character (see link). I have a column with a mix of typical and a null character. I'm trying to replace the null character with a different value. I would have thought that the following would work but it is unsuccessfull: select REPLACE(field_with_nullchar, char(0), ',') from FOO where BAR = 20

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  • sql error, NULL??

    - by Luke
    So I have a query, can someone let me know if it looks ok content wise? "INSERT INTO ".TBL_MESSAGES." (NULL, 'Your ranking points have changed', 'Due to your recent activity, your ranking points have increased by $r', '2', '$u', '0', '0', '0', '0', NULL, NULL, NULL, NULL, now())"; I can add further information if the query doesnt appear to have a problem? Thanks

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  • SSIS Null Value Questions

    - by Saobi
    I have a table with 5 string columns, all can be NULLs. After I read the data from this table, I want to convert any null values into empty strings. The reason is that I need to compare these columns with columns in another table of the same schema (using conditional split), and null values would cause the comparison to evaluate to NULL. Is there any functionality in SSIS that allows me to convert NULL's to empty strings, or just not having to deal with NULL's at all?

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  • Replace always replacing null values

    - by Mike
    Why does left(FIELD, replace(nullif(charindex('-', FIELD), 0), null, len(FIELD))) always return null? The idea behind the query is that if charindex() returns 0, then convert the results into null, then convert the null into the length of the field. So if '-' does not exist, show the whole string. For some reason it makes every row equal null. Thank you.

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  • Foreign keys and NULL in mySQL

    - by Industrial
    Hi everyone, Can I have a column in my values table (value) referenced as a foreign key to knownValues table, and let it be NULL whenever needed, like in the example: Table: values product type value freevalue 0 1 NULL 100 1 2 NULL 25 3 3 1 NULL Table: types id name prefix 0 length cm 1 weight kg 2 fruit NULL Table: knownValues id Type name 0 2 banana Note: The types in the table values & knownValues are of course referenced into the types table. Thanks!

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  • Timestamp Updating Constantly on /dev/null

    - by motorleague
    I've been working on a problem with a /dev/null file on an AIX system (just for background it looks as though it was inadvertently deleted and recreated as a normal file by somebody), but in trying to determine what caused the problem, I noticed that the timestamp on it seems to update every minute. I've observed this on several AIX servers at my workplace. At present I can't entirely rule out this be something specific to the Application being used at my workplace, so I compared with CentOS and Debian based computers at home last night. The CentOS box, which runs 24 hours, had a mod time on /dev/null of around 4 days ago (during which time it was essentially just being used as a web browser and multimedia player, although it would have had active but essentially unused Apache, MySQL and VMM processes running in the background). The timestamp on /dev/null on the Debian machine, which was a just booted laptop, pretty much reflected the boot time, but I tested redirecting STDIN from, and STDOUT to it, and the modification time was unchanged (I'm not sure 100% sure if directing data to /dev/null constitutes "writing to it" in the way it would a normal file). So my question is essentially, could anybody please offer any advice with regards to what circumstances (permissions changes etc.. aside) might cause the timestamp on /dev/null to update? Thanks very much for any suggestions. Alex.

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  • Unable to relate two MySQL tables (foreign keys)

    - by KPL
    Hello people, Here's my USER table CREATE TABLE IF NOT EXISTS `users` ( `id` int(11) NOT NULL AUTO_INCREMENT, `username` varchar(100) NOT NULL, `expiry` varchar(6) NOT NULL, `contact_id` int(11) NOT NULL, `email` varchar(255) NOT NULL, `password` varchar(100) NOT NULL, `level` int(3) NOT NULL, `active` tinyint(4) NOT NULL DEFAULT '1', PRIMARY KEY (`id`,`email`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ; And here's my contact_info table CREATE TABLE IF NOT EXISTS `contact_info` ( `id` int(11) NOT NULL AUTO_INCREMENT, `name` varchar(255) NOT NULL, `email_address` varchar(255) NOT NULL, `company_name` varchar(255) NOT NULL, `license_number` varchar(255) NOT NULL, `phone` varchar(30) NOT NULL, `fax` varchar(30) NOT NULL, `mobile` varchar(30) NOT NULL, `category` varchar(100) NOT NULL, `country` varchar(20) NOT NULL, `state` varchar(20) NOT NULL, `city` varchar(100) NOT NULL, `postcode` varchar(50) NOT NULL, PRIMARY KEY (`id`,`email_address`), ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ; The system uses username to login users.I want to modify it in such a way that it uses email for login. But there's no email_address in users table. I have added foreign key - email in user table(which is email_address in contact_info). How should I query database?

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  • ms-access: missing operator in query expression

    - by every_answer_gets_a_point
    i have this sql statement in access: SELECT * FROM (SELECT [Occurrence Number], [1 0 Preanalytical (Before Testing)], NULL, NULL,NULL FROM [Lab Occurrence Form] WHERE NOT ([1 0 Preanalytical (Before Testing)] IS NULL) UNION SELECT [Occurrence Number], NULL, [2 0 Analytical (Testing Phase)], NULL,NULL FROM [Lab Occurrence Form] WHERE NOT ([2 0 Analytical (Testing Phase)] IS NULL) UNION SELECT [Occurrence Number], NULL, NULL, [3 0 Postanalytical ( After Testing)],NULL FROM [Lab Occurrence Form] WHERE NOT ([3 0 Postanalytical ( After Testing)] IS NULL) UNION SELECT [Occurrence Number], NULL, NULL,NULL [4 0 Other] FROM [Lab Occurrence Form] WHERE NOT ([4 0 Other] IS NULL) ) AS mySubQuery ORDER BY mySubQuery.[Occurrence Number]; everything was fine until i added the last line: SELECT [Occurrence Number], NULL, NULL,NULL [4 0 Other] FROM [Lab Occurrence Form] WHERE NOT ([4 0 Other] IS NULL) i get this error: syntax error (missing operator) in query expression 'NULL [4 0 Other]' anyone have any clues why i am getting this error?

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  • Convert VARCHAR() columns to NVARCHAR()

    - by ChrisD
    We recently underwent an upgrade that required us to change our database columns from varchar to NVarchar, to support unicode characters. Digging through the internet, I found a base script which I modified to handle reserved word table names, and maintain the NULL/NotNull constraint of the columns.   I Ran this script use NWOperationalContent – Your Catalog Name here GO SELECT 'ALTER TABLE ' + isnull(schema_name(syo.id), 'dbo') + '.[' +  syo.name +'] '     + ' ALTER COLUMN [' + syc.name + '] NVARCHAR(' + case syc.length when -1 then 'MAX'         ELSE convert(nvarchar(10),syc.length) end + ') '+         case  syc.isnullable when 1 then ' NULL' ELSE ' NOT NULL' END +';'    FROM sysobjects syo    JOIN syscolumns syc ON      syc.id = syo.id    JOIN systypes syt ON      syt.xtype = syc.xtype    WHERE      syt.name = 'varchar'     and syo.xtype='U'   which produced a series of ALTER statements which I could then execute the tables.  In some cases I had to drop indexes, alter the tables, and re-create the indexes.  There might have been a better way to do that, but manually dropping them got the job done.   use NWMerchandisingContent GO ALTER TABLE Locale Drop Constraint PK_Locale ALTER TABLE Country DROP CONSTRAINT PK_Country GO ALTER TABLE dbo.[Campaign]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [UnitOfmeasure] NVARCHAR(200)  NULL; ALTER TABLE dbo.[BundleLocalization]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Imperative] NVARCHAR(MAX)  NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [Instructions] NVARCHAR(MAX)  NULL; ALTER TABLE dbo.[BundleComponentLocalization]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[BundleComponent]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Bundle]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Banner]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Video]  ALTER COLUMN [Link] NVARCHAR(512)  NOT NULL; ALTER TABLE dbo.[Video]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[ProductUsage]  ALTER COLUMN [VideoLink] NVARCHAR(512)  NOT NULL; ALTER TABLE dbo.[ProductUsage]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[Thumbnail]  ALTER COLUMN [ActorKey] NVARCHAR(200)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [Locale] NVARCHAR(8)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [UnitOfMeasure] NVARCHAR(150)  NOT NULL; ALTER TABLE dbo.[SkuLocalization]  ALTER COLUMN [SwatchColor] NVARCHAR(50)  NOT NULL; etc.. GO ALTER TABLE Locale ADD CONSTRAINT PK_Locale PRIMARY KEY (LocaleId) ALTER TABLE Country ADD CONSTRAINT PK_Country PRIMARY KEY (CountryId) Note that this alter is non-destructive to the data.   Hope this helps.

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  • How to make disabled or enabled on check box selection using jquery

    - by kumar
    Hello Friends, I am using this code to make enabling or disabling based on checkbox selection $('#Pchk').change(function() { var che =$('input[name=PMchk]').is(':checked'); if(!che) { $('fieldset').find("input,select,textarea").removeAttr('disabled'); } else { $('fieldset').find("input:not(:checkbox),select,textarea").attr('disabled', 'disabled'); $('#genericfieldset').find("input,select,textarea").removeAttr('disabled'); } }); Here is my Fieldset <fieldset calss="pricingM" id="PricingEditExceptions"> <div class="fiveper"> <label>FM#: <span><%=(null != a) ? Model.Asset.FundmasterSec : null%></span></label> <label>TNT#:<span><%=(null != a) ? Model.Asset.TNTSecurity: null%></span></label> <label>CUSIP#: <span><%=(null != a) ? Model.Asset.CUSIP :null%></span></label> <label>Asset:<span><%=(null != a) ? Model.Asset.AssetClassCode: null%></span></label> <label>Issue:<span><%=(null != a) ? Model.Asset.IssueType: null%></span></label> <label>COQ:<span><%=(null != a) ? Model.Asset.CodeCountryofQuotationName: null%></span></label> <label>CCY:<span><%=(null != a) ? Model.Asset.CurrencyCode: null%></span></label> <label>&nbsp;</label> </div> <div class="fiveper" id="display"> <input id="Pchk" type="checkbox" name="PMchk" value="<%=Model.ExceptionID%>" /> <label>ID#: <span><%=(null != a) ? Model.ExceptionID : 0%></span></label> <label for="ExceptionStatus"> Status: <span id="gui-stat-<%=Model.ExceptionID %>"> <%=Model.LookupCodes["C_EXCPT_STAT"].FirstOrDefault(model => model.Key.Trim().Equals(Model.ExceptionStatus.Trim())).Value%></span> </label> <label for="ResolutionCode"> Resolution: <span> <%=Html.DropDownListFor(model => model.ResolutionCode, new SelectList(Model.LookupCodes["C_EXCPT_RESL"], "Key", "Value", (null != Model.ResolutionCode) ? Model.ResolutionCode.Trim() : Model.ResolutionCode))%> </span> </label> <label for="ReasonCode"> Reason: <span><%=Html.DropDownListFor(model => model.ReasonCode, new SelectList(Model.LookupCodes["C_EXCPT_RSN"], "Key", "Value", (null != Model.ReasonCode) ? Model.ReasonCode.Trim() : Model.ReasonCode))%></span> </label> <label>Action Taken:<span><%=Html.DropDownListFor(model => model.ActionCode, new SelectList(Model.LookupCodes["C_EXCPT_ACT"], "Key", "Value", (null != Model.ActionCode) ? Model.ActionCode.Trim() : Model.ActionCode))%></span></label> <label>&nbsp;</label> </div> <div class="fiveper"> <label>Follow-Up:<span class="datepicker-container"><input type="text" id="exc-flwup-<%=Model.ExceptionID %>" name="exc-flwup-<%=Model.ExceptionID %>" value="<%=Model.FollowupDate %>" /></span></label> <label>Inqurity #: <span><%=Html.EditorFor(model => model.IOL)%></span> </label> <label>&nbsp;</label> <label>Comment: <span> <%=Html.TextAreaFor(model => model.Comment, new { })%> <%=Html.ValidationMessageFor(model => model.Comment)%> </span> </label> </div> <div id="hide" style="display:none"> <label><span><%=Model.Sequence %></span></label> <label><span><%=Model.AssignedId %></span></label> <span id="gui-stat-<%=Model.ExceptionID%>"> <%=Model.LookupCodes["C_EXCPT_STAT"].FirstOrDefault(model => model.Key.Trim().Equals(Model.ExceptionStatus.Trim())).Value%></span> <span>Last Updated:</span> <%=Model.LastUpdateUser.StartsWith("ATPB") ? "SYSTEM" : Model.LastUpdateUser%><br /> <%=Model.LastUpdated%> <% if (DateTime.Now.Date == Model.LastUpdated.Value .Date ) {%> <%=Math.Round((DateTime.Now - (DateTime)Model.LastUpdated).TotalHours, 0)%> hr<%} %> <p> <%=Html.EditorFor(model => model.SequenceDateTimeAsString)%> <%=Html.EditorFor(model => model.AssignedId)%> <span><%=Html.EditorFor(model => model.Origination)%></span> </p> </div> </fieldset> If I selct Four Users this Fieldset result will come in Four boxes....each box having Checkbox..Initially when the page loads I am disabling $('fieldset').find("input:not(:checkbox),select,textarea").attr('disabled','disabled'); ok with my Checkbox Change Funtion I am trying to make Enable or disable my Fieldset.. H here I need to handle Individual Fieldset based on Chekcbox.. right now If I select one check box all Fieldset inpu,select,texarea are making Disabled or Enable.. can anyone tell me how to handle Individual Fieldset on the same page/ thanks

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  • Why does this MySQL function return null?

    - by Shore
    Description: the query actually run have 4 results returned,as can be see from below, what I did is just concate the items then return, but unexpectedly,it's null. I think the code is self-explanatory: DELIMITER | DROP FUNCTION IF EXISTS get_idiscussion_ask| CREATE FUNCTION get_idiscussion_ask(iask_id INT UNSIGNED) RETURNS TEXT DETERMINISTIC BEGIN DECLARE done INT DEFAULT 0; DECLARE body varchar(600); DECLARE created DATETIME; DECLARE anonymous TINYINT(1); DECLARE screen_name varchar(64); DECLARE result TEXT; DECLARE cur1 CURSOR FOR SELECT body,created,anonymous,screen_name from idiscussion left join users on idiscussion.uid=users.id where idiscussion.iask_id=iask_id; DECLARE CONTINUE HANDLER FOR SQLSTATE '02000' SET done = 1; SET result = ''; OPEN cur1; REPEAT FETCH cur1 INTO body, created, anonymous, screen_name; SET result = CONCAT(result,'<comment><body><![CDATA[',body,']]></body>','<replier>',if(screen_name is not null and !anonymous,screen_name,''),'</replier>','<created>',created,'</created></comment>'); UNTIL done END REPEAT; CLOSE cur1; RETURN result; END | DELIMITER ; mysql> DELIMITER ; mysql> select get_idiscussion_ask(1); +------------------------+ | get_idiscussion_ask(1) | +------------------------+ | NULL | +------------------------+ 1 row in set (0.01 sec) mysql> SELECT body,created,anonymous,screen_name from idiscussion left join users on idiscussion.uid=users.id where idiscussion.iask_id=1; +------+---------------------+-----------+-------------+ | body | created | anonymous | screen_name | +------+---------------------+-----------+-------------+ | haha | 2009-05-27 04:57:51 | 0 | NULL | | haha | 2009-05-27 04:57:52 | 0 | NULL | | haha | 2009-05-27 04:57:52 | 0 | NULL | | haha | 2009-05-27 04:57:53 | 0 | NULL | +------+---------------------+-----------+-------------+ 4 rows in set (0.00 sec) For those who don't think the code is self-explanatory: Why the function returns NULL?

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  • Varchar columns: Nullable or not.

    - by NYSystemsAnalyst
    The database development standards in our organization state the varchar fields should not allow null values. They should have a default value of an empty string (""). I know this makes querying and concatenation easier, but today, one of my coworkers questioned me about why that standard only existed for varchar types an not other datatypes (int, datetime, etc). I would like to know if others consider this to be a valid, defensible standard, or if varchar should be treated the same as fields of other data types? I believe this standard is valid for the following reason: I believe that an empty string and null values, though technically different, are conceptually the same. An empty, zero length string is a string that does not exist. It has no value. However, a numeric value of 0 is not the same as NULL. For example, if a field called OutstandingBalance has a value of 0, it means there are $0.00 remaining. However, if the same field is NULL, that means the value is unknown. On the other hand, a field called CustomerName with a value of "" is basically the same as a value of NULL because both represent the non-existence of the name. I read somewhere that an analogy for an empty string vs. NULL is that of a blank CD vs. no CD. However, I believe this to be a false analogy because a blank CD still phyically exists and still has physical data space that does not have any meaningful data written to it. Basically, I believe a blank CD is the equivalent of a string of blank spaces (" "), not an empty string. Therefore, I believe a string of blank spaces to be an actual value separate from NULL, but an empty string to be the absense of value conceptually equivalent to NULL. Please let me know if my beliefs regarding variable length strings are valid, or please enlighten me if they are not. I have read several blogs / arguments regarding this subject, but still do not see a true conceptual difference between NULLs and empty strings.

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  • GWT Deserialisation of Persistent Entities (JPA)

    - by slartidan
    Hi everyone, I am currently developing Java/GWT-application which is hosted on a weblogic application server. I am using EJB3.0 with EclipseLink as persistence layer. Sadly my GWT has problems to deserialize persistent entities. It might be helpful for you to know, that I have the EclipseLink-Library in my classpath (including javax.persistence.Entity) am not recieving the persistence objects from a database or persistence-manager - I am creating the objects with standard java code use Eclipse IDE for Java EE Developers for development and deploying and I am compiling my GWT code with the GWT-Plugin (GWT 2.1.0) - my source code is split up in several projects am pretty sure, that the problems occures on client side, since the HTTP response of my server is the same in my working and in my not working example tried to patch javax.persistence.Entity and tried to include several libraries which included javax.persistence.Entity but nothing was helping In my server provides a list of instances of class SerialClass; the interface looks like this: public interface GreetingService extends RemoteService { List<SerialClass> greetServer(); } My onModuleLoad()-Method gets those instances and creates a browser-popup with the information: public void onModuleLoad() { GreetingServiceAsync server = (GreetingServiceAsync) GWT.create(GreetingService.class); server.greetServer(new AsyncCallback<List<SerialClass>>() { public void onFailure(Throwable caught) { } public void onSuccess(List<SerialClass> result) { String resultString = ""; try { for (SerialClass serial : result) { if (serial == null) { resultString += "null "; } else { resultString += ">" + serial.id + "< "; } } } catch (Throwable t) { Window.alert("failed to process"); } Window.alert("success:" + resultString); } }); } My server is looking like this: public class GreetingServiceImpl extends RemoteServiceServlet implements GreetingService { public List<SerialClass> greetServer() throws IllegalArgumentException { List<SerialClass> list = new ArrayList<SerialClass>(); for (int i = 0; i < 100; i++) { list.add(new SerialClass()); } return list; } } Case 1 = everything works fine I am using this SerialClass (either without any annotation, or with any annotation other than Entity - for example javax.persistence.PersistenceContext works fine): //@Entity public class SerialClass implements Serializable, IsSerializable { public int id = 4711; } The popup contains (as expected): success:>4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< >4711< The data sent over HTTP looks like this: //OK[4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,100,1,["java.util.ArrayList/3821976829","serial.shared.SerialClass/10650133"],0,6] Case 2 = its not working at all I am using this SerialClass: @Entity public class SerialClass implements Serializable, IsSerializable { public int id = 4711; } My popup contains (THIS IS MY PROBLEM): success:>2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null >2< null The data sent over HTTP looks like this (exactly the same!): //OK[4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,4711,2,100,1,["java.util.ArrayList/3821976829","serial.shared.SerialClass/10650133"],0,6] There is no suspicious logging output - neither on server, nor on client. All HTTP-responses have return code 200. My current workaround I am going to try to create transfer objects as a copy of my SerialClass - those transfer objects will look exactly the same, but will not have the @Entity annotation. Alternatively I could try to use the RequestFactory (thanks to @Hilbrand for the hint). I really don't know how to solve that problem and I'm really thankful about any suggestions, hints, tips, links, etc.

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