dbexpress

问题 This is probably a really simple question, but here it is. I just renewed my license for the DevArt DBExpress driver for Firebird. The help file says I can use their freeware DBMonitor application with it but since I am using D2006, I have to use these instructions: "If you are Delphi Pro version user, then you don't have TSQLMonitor component installed on the palette, but it is included in SQLExpr.pas unit and you need to install it on the components palette manually." I can create an

问题 I have been using DBExpress connections to various databases (mostly MSSQL, Sybase SQL) with: SQLConnection -> SQLDataSet -> DataSetProvider -> ClientDataSet. I need to connect to the databases in a fashion that does NOT write changes back to the tables. So, the DataSetProvider has ResolveToDataSet:=false, and the ClientDataSet has LogChanges:=false (for performance). In use I connect the SQLConnection, open the ClientDataSet, and then close the SQLConnection. I can then manipulate the

问题 Can I login to firebird database using a Windows user instead of using SYSDBA and MASTERKEY credential? If Yes, please let me know the way to connect to the firebird database. I am using Delphi XE3 and Firebird 2.5. I need to authenticate user by logged in user after updating config file for "trusted" in place of default "native" as specified here: https://firebirdsql.org/file/documentation/release_notes/html/en/2_5/rnfb25-fbconf-authent.html This is my code : SQLConnection1.LoginPrompt :=

问题 I'm using Firebird 2.1, DBExpress Driver from DevArt and Delphi 2010. Some of my reports that used to work with Delphi 2006 stopped working and produced an error message indicating that "arithmetic exception, numeric overflow, or string truncation" had occurred. The error occurred at this point in my code: cds.Data := dsProvider.Data; I found the place in my SQL statement that caused the error: iif(ytd.hPayType <> -1,t.sCode, 'NET') sPayType T.sCode is a Varchar(10) field. My conclusion is

问题 I am using DBExpress to connect to MySQL. I have a master detail relationship between two tables. I am providing the parent table via DatasetProvider. On the client side I have 2 clientdatasets. One of them accesses the provider, has all the parent field + the nested dataset field of the child. The second clientdataset Dataset field property is set to the nested dataset field of the parent. Now when I add a new record in the child dataset, it gives me an error "No corresponding master record

问题 I am using Delphi XE5 and I have created basic Firemonkey Mobile Application - Delphi I would like to connect to a remote MySQL database. Which if any database conduit do I use? (FireDAC, DBExpress, etc)? 回答1: You can use standard TSQLQueries, but as your mobile app needs to connect to a remote database, you will need to go via a DataSnap service (most probably hosted on an IIS server). The mobile device then connects to the DataSnap server which then connects to the database. The DataSnap

问题 By default, the TClientDataSet tracks all the changes made in the DataSet (inserts, updates, deletes). Is there a way to tell the dataset to accept the current changes (after a series of inserts using insert/post, let's say) without actually calling the database to save anything? One idea that I thought of was to use a TDataSetProvider and implement the BeforeUpdateRecord event and set the Applied parameter to true. I don't like two things about this. I have to add two more objects

问题 How do I find the reason for a "Record not found or changed by another user" error when working with dbExpress? How do I find the SQL statement (with the actual parameter values) that fails? 回答1: make sure that the compiler uses Debug DCUs. set a breakpoint in the first line of the Procedure TSQLResolver.DoExecSQL in unit db\Provider run the operation which causes the error message (for example, modifying a record in a data-aware component) if the debugger stops, the generated SQL command can

问题 I am running Delphi XE3 (Ultimate Edition) , MySQL database and this is the error I get when a click Test Connection . As a response, I located the libmysql library in my xampp directory and copied it over to my System32 directory. This does not work however. Which libraries/drivers is this message referring to and what is the correct directory to place them in? libmysql version - 5.5.16.0 回答1: The message states that the library could be: missing; not properly installed; or of the wrong

问题 I've got Delphi XE Professional. It comes with a fair amount of DBX stuff, including the DBXPool unit that contains the connection pooling support, but it doesn't have the full DBX support that comes in XE Enterprise. In particular, a lot of the design-time support isn't there. I don't particularly mind that. I've been able to do all the stuff I've needed without it, up until I needed connection pooling. Now I'm trying to get that to work and I can't quite figure out how to make it work. I