BorlandTalk.com Borland discussion newsgroups   Archives   FAQ   Search   Memberlist   Usergroups   Register   Profile   Log in to check your private messages   Log in  Access violation accessing value of timestamp field          BorlandTalk.com Forum Index -> Delphi Databases (InterBase Express) View previous topic :: View next topic   Author Message Andrew Lockwood Guest Posted: Mon Feb 12, 2007 7:13 pm    Post subject: Access violation accessing value of timestamp field Can anyone explain to me why, if I try to evaluate the value of an interbase timestamp field from within the IDE by placing the cursor over the code, I get an Access Violation? For example:- MyQuery.FieldByName(TimestampField).Value I appreciate that if I use AsDateTime instead of Value, I can avoid this problem, but I am writing a program where I need to use a variant, and I find this very frustrating / perplexing. I do not know if it is related, but on one of my computers, I now have the additional problem that the code has now started crashing on this line of code with an error EVA-1232 - some problem with the bordbk70.dll file. Back to top Wayne Niddery [TeamB] Guest Posted: Mon Feb 12, 2007 9:41 pm    Post subject: Re: Access violation accessing value of timestamp field Andrew Lockwood wrote: Quote: I appreciate that if I use AsDateTime instead of Value, I can avoid this problem, but I am writing a program where I need to use a variant, and I find this very frustrating / perplexing. In all seriousness, *why* must you use the variant property? Variants cannot properly distinguish between a TDateTime type and its root Double type and is a common source of problems for exactly this reason. You should do *anything* you can to avoid variants in general, but especially in the case of dates and times. -- Wayne Niddery - Winwright, Inc (www.winwright.ca) "Bandwagons are like streetcars, there'll be another along in a few minutes." Back to top Andrew Lockwood Guest Posted: Tue Feb 13, 2007 12:54 am    Post subject: Re: Access violation accessing value of timestamp field I am reading values from my dataset into an array, and I need the array to be flexible so that it can hold different types of data. I could easily recode it to read MyArray[Count].Value := IBXDataset.FieldByName(TimestampField).AsDateTime But would this make any difference if I am still storing the value as a variant? Andrew Lockwood "Wayne Niddery [TeamB]" <wniddery (AT) chaffaci (DOT) on.ca> wrote in message news:45d08ab9 (AT) newsgroups (DOT) borland.com... Quote: Andrew Lockwood wrote: I appreciate that if I use AsDateTime instead of Value, I can avoid this problem, but I am writing a program where I need to use a variant, and I find this very frustrating / perplexing. In all seriousness, *why* must you use the variant property? Variants cannot properly distinguish between a TDateTime type and its root Double type and is a common source of problems for exactly this reason. You should do *anything* you can to avoid variants in general, but especially in the case of dates and times. -- Wayne Niddery - Winwright, Inc (www.winwright.ca) "Bandwagons are like streetcars, there'll be another along in a few minutes." Back to top Wayne Niddery [TeamB] Guest Posted: Tue Feb 13, 2007 4:10 am    Post subject: Re: Access violation accessing value of timestamp field Andrew Lockwood wrote: Quote: I am reading values from my dataset into an array, and I need the array to be flexible so that it can hold different types of data. I could easily recode it to read MyArray[Count].Value := IBXDataset.FieldByName(TimestampField).AsDateTime But would this make any difference if I am still storing the value as a variant? Going in this direction I'm not sure if there is a problem (other than variants are slower). Going back into the database field object though is where I often see problems - i.e. converting from a variant to a datetime. If you consistently use the AsXXX properties in the TFields, that might be enough to avoid problems even though they are going to/coming from variants, but I don't know that for sure - I had enough problems with variants very early on that I've avoided them completely since then. -- Wayne Niddery - Winwright, Inc (www.winwright.ca) "Democracy, without the guarantee of liberty, is merely a method of selecting tyrants." - Alan Nitikman Back to top Display posts from previous: All Posts1 Day7 Days2 Weeks1 Month3 Months6 Months1 Year Oldest FirstNewest First         BorlandTalk.com Forum Index -> Delphi Databases (InterBase Express) All times are GMT Page 1 of 1   Jump to: Select a forum C++ Builder Newsgroups----------------C++ BuilderC++ Builder (ActiveX)C++ Builder (Announcements)C++ Builder (Command Line Tools)C++ Builder DatabasesC++ Builder Databases (ADO)C++ Builder Databases (Desktop)C++ Builder Databases (InterBase Express)C++ Builder Databases (Multi-Tier)C++ Builder Databases (SQL Servers)C++ Builder (Graphics)C++ Builder (IDE)C++ Builder (Internet)C++ Builder (Internet Socket)C++ Builder (Internet Web)C++ Builder (Jobs)C++ Builder (Language)C++ Builder (Language C++)C++ Builder (Compatibility with MFC)C++ Builder (Native API)C++ Builder (Non-Technical)C++ Builder (Students)C++ Builder (Third Party Tools)C++ Builder (Upgrade)C++ Builder (VCL)C++ Builder (VCL Components Usage)C++ Builder (VCL Components Development)C++ Builder (VCL Usage)C++ Builder (WinAPI)C++ Builder Installation Delphi Newsgroups----------------Delphi (General)Delphi ActiveX Controls UsageDelphi ActiveX Controls DevelopmentDelphi As400Delphi DatabasesDelphi Databases (ADO)Delphi Databases (dbExpress)Delphi Databases (Desktop)Delphi Databases (InterBase Express)Delphi Databases (Multi-Tier)Delphi Databases (SQL Servers)Delphi DeploymentDelphi GraphicsDelphi IDEDelphi InternationalizationDelphi InternetDelphi Internet Isapi-WebBrokerDelphi Internet WebSnapDelphi Internet WinsockDelphi JobsDelphi Language BASMDelphi Language ObjectPascalDelphi Model Driven Architecture (General)Delphi Model Driven Architecture (Third Party)Delphi MultimediaDelphi Native APIDelphi Non-TechnicalDelphi ObjectPascalDelphi OLE AutomationDelphi OO designDelphi OpenToolsAPIDelphi Reporting-ChartingDelphi RTLDelphi StudentsDelphi TeamSourceDelphi Thirdparty ToolsDelphi Thirdparty Tools (General)Delphi Thirdparty Tools (IntraWeb)Delphi Thirdparty Tools (RaveReports)Delphi UpgradeDelphi VCLDelphi VCL ComponentsDelphi VCL Components UsingDelphi VCL Components WritingDelphi WebServices SOAPDelphi WinAPIDelphi XMLDelphi Installationcomp.lang.pascal.delphi.components.misccomp.lang.pascal.delphi.components.usagecomp.lang.pascal.delphi.components.writingcomp.lang.pascal.delphi.databasescomp.lang.pascal.delphi.misccomp.sources.delphi JBuilder Newsgroups----------------JBuilderJBuilder AnnouncementsJBuilder Applet IssuesJBuilder As400JBuilder CompilerJBuilder CORBA/RMIJBuilder DatabasesJBuilder DB SwingJBuilder DebuggerJBuilder DeploymentJBuilder DocumentationJBuilder EnterpriseJBuilder HandheldJBuilder IDEJBuilder JavaJBuilder JavaAPIJBuilder Java LanguageJBuilder Java SwingJBuilder Java BeansJBuilder Java Beans UsageJBuilder Java Beans DevelopmentJBuilder JBCLJBuilder JDataStoreJBuilder JobsJBuilder LinuxJBuilder MacintoshJBuilder & MobileSetJBuilder MultiLingual AppsJBuilder Non-TechnicalJBuilder OpenToolsJBuilder Servlets (JSP)JBuilder StudentsJBuilder Team DevelopmentJBuilder Thirdparty ToolsJBuilder UpgradeJBuilder Installation InterBase Newsgroups----------------InterBaseInterBase Bug DiscussionInterBase GeneralInterBase IBConsoleInterBase OpenSourceInterBase ReplicationInterBase SQLInterBase ThirdpartyInterBase Installation Miscellaneous Borland Newsgroups----------------AppCenterAppServerEnteraVisiBroker  You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum Powered by phpBB © 2001, 2006 phpBB Group SEO toolkit © 2004-2006 webmedic.