Serguei_Tarassov's blog

Types of joins in SQL (cheatsheet for beginners)

Better to see once than to hear a hundred times. This small article explains what are the different kinds of joins in SQL.

At the first time you should take into account that SQL is a declarative 4th generation language. So the best way to use it (especially for beginners) is to write the query and let SQL optimizer do its job. That means thinking in set-oriented terms and avoiding sub-queries.

Let's take two example tables: Companies and Contacts.

Delphi Starter doesn't support command line

Delphi feature matrix has two important points:

  • Delphi 32-bit native code optimizing compiler (dcc32) for Windows, including high performance x86
    Assembler
  • Delphi toolchains for Windows

Regardless indicated options dcc32 doesn't work in Delphi Berlin Starter with the error message "This version of the product does not support command line compiling".

Installing Delphi 7 on Windows 7/8/10/Server 2012

How to install and use Delphi 7 and help files on Windows 8/10 or Server 2012.

Installation

Start Delphi setup and install all required items including help files.

In Windows 8/Server 2012 or later (should work on Windows 7 too):

  • Create the shortcut to Delphi32.exe
  • Open shortcut properties and set "run as administrator" option
  • Add Delphi to the of DEP (Data Execution Prevention). Go to My Computer - Properties - Advanced System Settings - Performance Settings - Data Execution Prevention

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