MyFiles

Properties

Definition

A property is the most important object Argentum MyFiles operates with. Knowing it is essential if you want to get most out of Argentum MyFiles. A property is an object containing three entities:

1. name of the property
2. declaration of the property
3. data

The name of the property is a text string used as a property alias.

The declaration of the property is defined by the major property type and additional property type modifiers which supplement this declaration. A set of possible modifiers are defined by its major type. There are seven major types, with modifiers extending the set of all possible types up to over twenty. The number of modifiers may vary from zero to two depending upon the major type. Modifiers may be either integer numbers or text strings.

The data is the information itself, which the given property represents. Its volume, interpretation, and representation depends directly upon the property declaration.

The name of the property and declaration of the property entities make up the property header. The property is therefore an object containing the header and data. The header of the property is coded by a text string using the following format: "Name of the property, Character defining major type of the property, Zero to two type modifiers delimited by comma (,) signs".

Declaration matrix

Examples

• "Name,s,30,1" . Edit control with a horizontal size of 30 characters and vertical size of 1 character is used for representing and editing textual strings.
• "Information,s,60,25" . Memo control with horizontal size of 60 characters and vertical size of 25 characters is used for representing and editing textual data.
• "ID,i,4,10" . Edit control is used for representing and editing decimal integer numbers occupying 4 bytes.
• "Check,i,4,16" . Edit control is used for representing and editing hexadecimal integer numbers occupying 4 bytes.
• "Release date,d" . Edit control is used for representing and editing dates.
• "Distribution,c,Licensed;Shareware;Trialware;Freeware" . Combo-box control with options listed between semicolon (;) signs.
• "Platform,e,MS-DOS;Win16;Win32;Win64;Unix;OS/2" . Check-box control with check options listed between semicolon (;) signs.

Property table

Argentum MyFiles has an ability to emphasize frequently used properties by means of a predefined property table. Such emphasized properties are called indexed properties and have a corresponding property table. Property headers are stored in a special property table and every such header has its own unique index. Rows of that table are specified as "Index, Header". Later, when it is necessary to create or access a frequently used property, this property is addressed not by its header, but by its index solely. In real life it is recommended to index not only frequently used properties but all properties which you are planning to use with your tree. Indexing is beneficial as it simplifies working with properties, minimizes storage expenses, and makes the processing much faster.

It is better to plan out your property table before you begin working with your tree since later corrections may cause conflicts in the interpretation of a newly corrected property table (the tree items data may remain indexed by the old table). This warning is only applicable to the indexed headers that were already used in your tree. You may safely delete or edit in any way those headers that you are sure are not used yet. You may always extend a property table with new headers using unique indexes without worry. You may even change textual portions of already used headers in a tree's property table provided that no structural modifications are done. However it is still a good general rule to plan your property layout before populating your tree with the information.

Basic properties

Argentum MyFiles offers the user the ability to add and index their own customizable properties based upon personal preferences. However a small set of basic properties have a strictly predetermined meaning. You are not permitted to delete or edit the structure of the headers of these properties as Argentum MyFiles uses them automatically and expects their availability. Indexes from 0 to 14 are currently reserved for basic properties. You will see their headers in the property table of every Argentum MyFiles tree. All you are allowed to alter with these headers is their textual portions provided that no structural modifications are done.

Nodal item

A nodal item is a root item of the tree. It stores a property table for that tree, along with other important information. The ID of this item is always 1 and the parent ID is always 0 (i. e. parent item is absent). The nodal item has some limitations; for example, any indexed property of that item must only be a basic property - all other properties must be non-indexed. Furthermore, whilst editing the property table you should bear in mind the restrictions placed upon the basic properties and take into account all the rules concerning the table (see above topics). Argentum MyFiles checks most modifications you perform on the nodal item and notifies you if they are incorrect. Changes in the property table take effect after the tree has been re-opened.

Argentum MyFiles is designed to give the user unified methods for querying subsets of properties where it is required. There are two major methods: filters and lists. Filters are defined by using a combination of up to three primary components:

1. Names of filtered properties are specified in the form of a list from top to bottom (order has no meaning).
2. If it is necessary to filter all available properties you have to specify asterisk (*) on an extra line.
3. If you are specifying asterisk (*), you may wish to exclude some properties from your query. Simply specify the excluded properties preceded with a minus (-).

A property list is just an enumeration of all the necessary properties one after another.

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