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Brian Evans

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Posts posted by Brian Evans

  2. Posted

    Introducing new variables isn't the same as WITH which just adjusts how the compiler handles scoping for which reference a name refers to at compile time. 

     

    If introducing a new variable isn't an issue may as well use inline variables with type inference for modern Delphi at least.  

    procedure TMyForm.UpdateInventoryItem(const NewQty: Integer);
begin
  var A := dmStoreInventoryData;
  var B := A.tblUpdateItemForStore;
  B.Edit;
  B.FieldByName('Qty').AsInteger := NewQty;
  B.Post;
end;

     

    • Confused 1

  3. Posted

    2 hours ago, Darian Miller said:

    My guess is that Aliasing would bring in a new set of problems but if it's just a preprocessor type replacement, it might be OK.  

    But look at your example code - what is the scope of "NewQty"?  Does it belong to A, to B, or to the Form, or to a variable or method somewhere?  If it doesn't belong to A or B, what if "NewQty" is added to A or B as a property or method later?  Boom, your with-bomb will explode into a nice bug.

     

    In this example NewQty is a parameter of the procedure.  

  4. Posted

    If they added the ability to provide an alias the ambiguity would be gone. Aliases in SQL are useful and perform a similar function. Shortening repeated references can make code easier to read, the problem is the current WITH creates ambiguity. 

    A code snipped from the blog post redone with the ability to provide an alias as an example: 

    procedure TMyForm.UpdateInventoryItem(const NewQty: Integer);
begin
  with dmStoreInventoryData as A do begin
    with A.tblUpdateItemForStore as B do begin
      B.Edit;
      B.FieldByName('Qty').AsInteger := NewQty;
      B.Post;
    end;
  end;
end;

     

    • Like 5

  6. Posted

    FireDac requires client libraries of some form provided by Microsoft to access Microsoft SQL Server. These are not available for Android. 

     

    Another set of data access components is SDAC from Devart which has an additional direct access mode that uses TCP/IP directly to access Microsoft SQL Server. Applications using this direct mode can run on platforms for which Microsoft has not provided client libraries.

     

     

  7. Posted

    I think those (uses-feature) are just play store hints? The application won't be offered to devices without the uses features that are marked as required. They don't seem to be used by the android loader itself. 
    Might be the OS is trying to be clever and attempting to pre-load/integrate something related to a uses-feature that then causes issues or a crash. 

    • Like 1

  8. Posted

    Using SQL to query <100k records in a memory table shouldn't be slow on even a 300Mhz Pentium 2 with spinning rust with even a small number of indexes to help. 

    I wonder what you are doing to make it so slow. 

     

    Something like SQLite is well optimized and shouldn't be slow at this, especially if you load the data into in-memory tables and add an index or two.  

     

  9. Posted

    Work on describing the problem. Start with conditions where it occurs, Where does it not occur? Describe "What" the problem is. Develop a small test case or program you can share that reproduces the problem. Reproduce the problem yourself in varied environments.

  11. Posted

    A quick search I see that information at codesnip-faq/UsingCodeSnip.md at master · delphidabbler/codesnip-faq · GitHub in part of the answer to 

     

    FAQ 3
    What changes does CodeSnip make to my system?

     

    Quote

     

    • A %ProgramData%\DelphiDabbler\CodeSnip.4 folder is created. A configuration file is stored in the folder. Once the database is downloaded, its files will be stored in a Database sub-folder (see below).

    • A %AppData%\DelphiDabbler\CodeSnip.4 folder is also created. This is used to hold a file that stores per-user configuration data. A UserDatabase sub-folder is used to store any user defined snippets. Note: From CodeSnip 4.3.0 the user can change the directory containing the user-defined snippets.


     

     

  14. Posted · Edited by Brian Evans

    It shows live data. For ONE field of ONE record (the current record of the dataset) it shows a list of values (from the items property) with the current field value highlighted. 

     

    A customer record might have a Country field: hooking it up with the list having values for Canada, USA, Mexico it would highlight the list value matching that of the current record. If the user clicked a different list value, then the field would change value to that. 

  15. Posted · Edited by Brian Evans

    You need to put the list of values to choose from in the list's items property.

    Quote

     

    TDBListBox represents a data-aware list box that allows users to change field values by selecting an item from a list.

    Use TDBListBox to add a list box to a form that permits users to change the value of a field on the current record to one of a fixed set of choices.

     

    If you want the list of values to come from the database you would use a DBLookupListBox. 

  22. Posted

    The DLL it is running, and its location should give some hints as to what it is as will the contents (strings at least) of that DLL. Best to figure out what it is and uninstall or disabled it. 

     

    Sometimes software is installed as a device driver, I remember an annoying piece of Lenovo software that was like that. 

    Other things that can eat a lot of disk IO would be Windows Search indexing. 

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