# 4th Dimension (software)

4D (4th Dimension, or Silver Surfer, as it was known during early development) is a relational database management system and integrated development environment developed by Laurent Ribardière. 4D was created in 1984 and had a slightly delayed public release for Macintosh in 1987 with its own programming language.
The 4D product line has since expanded to an SQL back-end, integrated compiler, integration of PHP, and several productivity plug-ins and interfaces. Some of the plug-ins created by 4D include 4D Write (a word processor), 4D View (somewhat like a spreadsheet, but with extra functionality) and 4D Internet Commands (which allowed for the addition of Internet-related functionality to a database). There are also over 100 third-party plugins, free and commercial.
4D can also be used as a web server, to run compiled database applications.
Today, 4D is published by the French company 4D SAS and has a sales, distribution and support presence in most major markets, with the United States, the United Kingdom, and France being the primary markets. The product is localized in more than a dozen languages.

## History

Silver Surfer, as it was known during early development, was developed by Laurent Ribardière in 1984. Following negotiations with Ribardiere it was planned that Apple Inc. (formerly Apple Computer Inc) would publish the software but Apple canceled the plan, reportedly due to pressure from other potential database publishers who claimed that if Apple had their own "brand" database, third party products would be disadvantaged in the marketplace. Apple tried at the time to ensure well-known software publishers supported the Macintosh platform, and as a result the project reverted to Laurent Ribardière, who with the French businesswoman Marylene Delbourg-Delphis published 4th Dimension. Although independently published, Apple supported the new venture and used 4D extensively throughout the organization for projects including fitness center management and CIM (Computer Integrated Manufacturing). A number of Apple personnel became 4D experts, including Lance McAndrew in Apple's Cupertino headquarters and Andrew O'Donoghue in Apple's Ireland-based European manufacturing headquarters, where a 4th Dimension application managed the European Service Center administration.
Over the next few years 4th Dimension's installed base grew, and the publisher ACI established a US-based subsidiary called ACIUS, initially led by Guy Kawasaki. After 16 years of operating as ACIUS up to 2000, the name was officially changed to 4D Inc.
In 1993, 4D Server v1.1, the client/server version of 4th Dimension was introduced along with the release of 4th Dimension v3.1.
In 1995, 4D v3.5 went cross-platform and has since then supported both the Microsoft Windows and Apple Macintosh operating systems.
In 1997, 4D v6 was the first version of 4D to contain a fully integrated web server, allowing developers to translate 4D forms into HTML on the fly using only the 4D language.
In 2004, 4D 2004 was the first version of 4D to allow developers to create standalone, client/server, web and Service Oriented Applications (SOA) without changing any code.
In 2008, 4D v11 added a SQL layer to the 4D database engine and extending native SQL in to the 4D programming language which allowed 4D developers to write native SQL code to connect to either local or remote servers.
In 2010, 4D v12 integrated the ability to execute PHP functions/scripts from within the 4D programming language. This version also supported new replication and synchronization commands and included a 64 bit version of 4D Server.

### Version history

| Branch | Latest version | Initial release | Final release | Status Feb 2022 | Notes |
| v19.x | v19.LTS | 12 Jul 2021 | Ongoing | Supported | Native support for Apple Silicon, Classes |
| v18.x | v18.LTS | 16 Jan 2020 | Ongoing | Supported | Project Databases for Version Control, Built-in encryption tools, 4D for iOS, 4D Write Pro, 4D View Pro |
| v17.x | v17.4 | 10 July 2018 | 13 Dec 2020 (4D v17.5) | Support ended 13 Dec 2020 | ORDA (Object Relational Data Access), Collections, Object Notation, Dynamic forms |
| v16.x | v16.6 | 10 Jan 2017 | 24 Jul 2019 (4D v16.6) | Support ended 24 July 2019 | New Cache Management System, Preemptive Multithreading, 4D Dev Pro 64 bit |
| v15R | v15R5 | 10 Nov 2015 | 14 Sep 2016 | Superseded by 16.x | Preview of features to be in v16.x |
| v15.x | v15.6 | 16 Jul 2015 | 25 Apr 2017 | Support ended 25 Apr 2018 | 64 bit 4D Server for Mac servers; New network layer |
| v14R | v14R5 | May 2014 | March 2015 | No longer supported | preview of features to be in v15.x |
| v14.x | v14.6 | 12 Dec 2013 | 20 Dec 2016 | No longer supported | 4D Mobile (Connectivity options for 4D Server as a datasource for Wakanda (software)); Structured JSON objects (C_Object); SQL views; new tools for maintenance and monitoring, new journaling system. |
| v13.x | v13.6 | 14 Feb 2012 | 18 Jun 2015 | No longer supported | New multithreaded HTTP server; automatic session management; new extensible HTTP client; webkit integration and extended Javascript support; enriched list box; external document management. |
| v12.x | v12.6 | 3 Jun 2010 | 8 Oct 2013 | No longer supported | 64 bit 4D Server for Windows servers; PHP integration; Synchronization and Replication |
| v11.x | v11.9 | 23 Sep 2008 | 7 Jul 2011 | No longer supported | SQL engine; integrated maintenance center (MSC); SVG management; Integrated Web Area |
| 2004.x | 2004.8 | 31 Aug 2004 | 30 Jun 2009 | No longer supported | Revamped interface; Integration of high-level ODBC commands, 4D Customizer, 4D Backup and 4D Engine |
| 2003.x | 2003.8r2 | 17 Mar 2003 | 11 Apr 2006 | No longer supported | XML; Web Services; Embedded Compiler |
| v6.8.x | 6.8.6 | 15 Apr 2002 | 24 Sep 2004 | No longer supported | |
| v6.7.x | 6.7.5 | | | No longer supported | |
| v6.5.x | | 18 May 1999 | | No longer supported | |
| v6.0.x | 6.0.5 | 1997 | 27 Feb 1998 | No longer supported | Integrated Web Server |
| v3.x | | | | No longer supported | 4D v3.5 was the first cross-platform version (mac/win), |
| v1.x | | 1987 | | No longer supported | Mac only |

## Architecture

A 4D application can run in either Standalone mode or Client-Server mode.

### Single-User

In Standalone mode, the 4D application (4D.exe on Windows or 4D.app on Mac) is used to open the structure file (4DB/4DC) file directly along with the associated data file (4DD).

### Client-Server

In the Client-Server paradigm the 4D Server application (4DServer.exe on Windows or 4DServer.app on Mac) is used to open the structure file (4DB/4DC) file directly along with the associated data file (4DD). 4D may then be used in remote mode to connect to the 4D Server.

## Application Editions

4D has two applications; 4D and 4D Server. 4D Server runs only as a server but 4D can be run in either standalone or remote mode.

### 4D

4D can be run in two modes. 4D in single-user mode allows for 1 person to run the application. 4D in remote mode is used for connecting to a 4D Server.

### 4D Server

4D Server is used for Client-Server connectivity to the application. In this mode, 4D Server loads the structure file (4DB or 4DC) and also the datafile (4DD) and provides network access to 4D (in remote). Each workstation has a dynamically updated cache of the resources they are working with, while the 4D Server maintains the data and code.

## Syntax

This section will include syntax examples demonstrating different programming constructs used in 4D, such as for loops and variable usage.

### Data Types

4D fields, variables, and expressions can be of the following data types:
| Data Type | Field | Variable | Expression |
| String | Yes | Yes | Yes |
| Number (double) | Yes | Yes | Yes |
| Date | Yes | Yes | Yes |
| Time | Yes | Yes | Yes |
| Boolean | Yes | Yes | Yes |
| Picture | Yes | Yes | Yes |
| Pointer | No | Yes | Yes |
| BLOB | Yes | Yes | No |
| Array | No | Yes | No |
| Integer 64 bits | Yes | No | No |
| Float | Yes | No | No |
| Object | Yes | Yes | Yes |
| Collection | Yes | Yes | Yes |
| Undefined | No | Yes | Yes |
More info on 4D data type can be found on the [ 4D Data Types] documentation page

### Variable Scope

Local variables are prefixed with a $ like $myLocalVariable and only live for the duration of the method.
Process variables have no prefix like myProcessVariable and live throughout the duration of the process.
Inter-process (or Global) variables are prefixed with a <> like <>myGlobalVariable and live throughout the duration of the application.

### Comparison of looping
#### Nested Loops

The following example goes through all the elements of a two-dimensional array:
The following example builds an array of pointers to all the date fields present in the database: