Architecture of a 4D project

A 4D project is made of several folders and files, stored within a single parent database folder (package folder). For example:

• MyProject
  • Components
  • Data
    • Logs
    • Settings
  • Documentation
  • Plugins
  • Project
    • DerivedData
    • Sources
    • Trash
  • Resources
  • Settings
  • userPreferences.username
  • WebFolder

If your project has been converted from a binary database, additional folders may be present. See "Converting databases to projects" on doc.4d.com.

Project folder

The Project folder typically contains the following hierarchy:

• databaseName.4DProject file
• Sources
  • Classes
  • DatabaseMethods
  • Methods
  • Forms
  • TableForms
  • Triggers
• DerivedData
• Trash (if any)

databaseName.4DProject file

Project development file, used to designate and launch the project. This file can be opened by:

• 4D Developer
• 4D Server (read-only, see Developing a project)

Note: In 4D projects, development is done with 4D Developer and multi-user development is managed through source control tools. 4D Server can open .4DProject files for testing purposes.

Sources folder

Contents	Description	Format
catalog.4DCatalog	Table and field definitions	XML
folders.json	Explorer folder definitions	JSON
menus.json	Menu definitions	JSON
settings.4DSettings	Structure database settings. They are not taken into account if user settings or user settings for data are defined. Warning: In compiled applications, structure settings are stored in the .4dz file (read-only). For deployment needs, it is necessary to use user settings or user settings for data to define custom settings.	XML
tips.json	Defined tips	JSON
lists.json	Defined lists	JSON
filters.json	Defined filters	JSON
styleSheets.css	CSS style sheets	CSS
styleSheets_mac.css	Mac css style sheets (from converted binary database)	CSS
styleSheets_windows.css	Windows css style sheets (from converted binary database)	CSS

DatabaseMethods folder

Contents	Description	Format
databaseMethodName.4dm	Database methods defined in the database. One file per database method	text

Methods folder

Contents	Description	Format
methodName.4dm	Project methods defined in the database. One file per method	text

Classes folder

Contents	Description	Format
className.4dm	User class definition method, allowing to instantiate specific objects. One file per class, the name of the file is the class name	text

Forms folder

Contents	Description	Format
formName/form.4DForm	Project form description	json
formName/method.4dm	Project form method	text
formName/Images/pictureName	Project form static picture	picture
formName/ObjectMethods/objectName.4dm	Object methods. One file per object method	text

TableForms folder

Contents	Description	Format
n/Input/formName/form.4DForm	Input table form description (n is the table number)	json
n/Input/formName/Images/pictureName	Input table form static pictures	picture
n/Input/formName/method.4dm	Input table form method	text
n/Input/formName/ObjectMethods/objectName.4dm	Input form object methods. One file per object method	text
n/Output/formName/form.4DForm	Output table form description (n is the table number)	json
n/Output/formName/Images/pictureName	Output table form static pictures	picture
n/Output/formName/method.4dm	Output table form method	text
n/Output/formName/ObjectMethods/objectName.4dm	Output form object methods. One file per object method	text

Triggers folder

Contents	Description	Format
table_n.4dm	Trigger methods defined in the database. One trigger file per table (n is the table number)	text

Note: The .4dm file extension is a text-based file format, containing the code of a 4D method. It is compliant with source control tools.

Trash folder

The Trash folder contains methods and forms that were deleted from the project (if any). It can contain the following folders:

• Methods
• Forms
• TableForms

Within these folders, deleted element names are in parentheses, e.g. "(myMethod).4dm". The folder organization is identical to the Sources folder.

DerivedData folder

The DerivedData folder contains cached data used internally by 4D to optimize processing. It is automatically created or recreated when necessary. You can ignore this folder.

Resources folder

The Resources folder contains any custom database resource files and folders. In this folder, you can place all the files needed for the translation or customization of the application interface (picture files, text files, XLIFF files, etc.). 4D uses automatic mechanisms to work with the contents of this folder, in particular for the handling of XLIFF files and static pictures. For using in remote mode, the Resources folder lets you share files between the server machine and all the client machines. See the 4D Server Reference Manual.

Contents	Description	Format
item	Database resource files and folders	various
Images/Library/item	Pictures from the Picture Library as separate files(*). Names of these items become file names. If a duplicate exists, a number is added to the name.	picture

(*) only if the project was exported from a .4db binary database.

Data folder

The data folder contains the data file and all files and folders relating to the data.

Contents	Description	Format
data.4dd(*)	Data file containing data entered in the records and all the data belonging to the records. When you open a 4D project, the application opens the current data file by default. If you change the name or location of this file, the Open data file dialog box will then appear so that you can select the data file to use or create a new one	binary
data.journal	Created only when the database uses a log file. The log file is used to ensure the security of the data between backups. All operations carried out on the data are recorded sequentially in this file. Therefore, each operation on the data causes two simultaneous actions: the first on the data (the statement is executed normally) and the second in the log file (a description of the operation is recorded). The log file is constructed independently, without disturbing or slowing down the user’s work. A database can only work with a single log file at a time. The log file records operations such as additions, modifications or deletions of records, transactions, etc. It is generated by default when a database is created.	binary
data.match	(internal) UUID matching table number	XML

(*) When the project is created from a .4db binary database, the data file is left untouched. Thus, it can be named differently and placed in another location.

Settings folder

This folder contains user settings files for data used for database administration.

These settings take priority over user settings files and structure settings files.

Contents	Description	Format
Backup.4DSettings	Database backup settings, used to set the backup options) when the database is run with this data file. Keys concerning backup configuration are described in the 4D XML Keys Backup manual.	XML
settings.4DSettings	Custom database settings for this data file	XML
directory.json	Description of 4D groups, users, and their access rights when the database is run with this data file.	JSON

Logs folder

The Logs folder contains all log files used by the project. Log files include, in particular:

• database conversion,
• web server requests,
• backup/restore activities journal (Backup Journal[xxx].txt, see Backup journal)
• command debugging,
• 4D Server requests (generated on client machines and on the server).

An additional Logs folder is available in the system user preferences folder (active 4D folder, see Get 4D folder command) for maintenance log files and in cases where data folder is read-only.

Settings folder

This folder contains user settings files used for database administration. File are added to the folder when necessary.

If a data settings file exists in a Settings folder in the data folder, it takes priority over user settings file.

Contents	Description	Format
directory.json	Description of 4D groups and users for the database, as well as their access rights	JSON
BuildApp.4DSettings	Build settings file, created automatically when using the application builder dialog box or the BUILD APPLICATION command	XML
Backup.4DSettings	Database backup settings, used to set the backup options) when each backup is launched. This file can also be used to read or set additional options, such as the amount of information stored in the backup journal. Keys concerning backup configuration are described in the 4D XML Keys Backup manual.	XML
BuildApp.4DSettings	Build settings file, created automatically when using the application builder dialog box or the BUILD APPLICATION command	XML

userPreferences.userName folder

This folder contains files that memorize user configurations, e.g. break point or window positions. You can just ignore this folder. It contains for example:

Contents	Description	Format
methodPreferences.json	Current user method editor preferences	JSON
methodWindowPositions.json	Current user window positions for methods	JSON
formWindowPositions.json	Current user window positions for forms	JSON
workspace.json	List of opened windows; on macOS, order of tab windows	JSON
debuggerCatches.json	Caught calls to commands	JSON
recentTables.json	Ordered list of tables	JSON
preferences.4DPreferences	Current data path and main window positions	XML

Components folder

This folder contains the components to be available in the project database only. It must be stored at the same level as the Project folder.

A project database can be used itself as a component:

• for development: put an alias of the .4dproject file in the Components folder of the host database.
• for deployment: build the component (see Building a project package) and put the resulting .4dz file in a .4dbase folder in the Components folder of the host database.

Plugins folder

This folder contains the plug-ins to be available in the project database only. It must be stored at the same level as the Project folder.