Difference between revisions of "MetaProperty"
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===Floating point=== | ===Floating point=== | ||
| − | [http://en.wikipedia.org/wiki/Double-precision_floating-point_format Double-precision floating-point format], optionally with unit of measurement that can be configured with the setting [[#Unit Item]]. | + | [http://en.wikipedia.org/wiki/Double-precision_floating-point_format Double-precision floating-point format], optionally with unit of measurement that can be configured with the setting [[#Unit Item|Unit item]]. |
===File reference=== | ===File reference=== | ||
Revision as of 07:36, 15 October 2013
Contents
Basics
In UBIK®, a MetaProperty describes a single feature of a certain MetaClass. A MetaProperty will never hold own values, but it serves as a definition for a resulting BaseProperty on a derived ContentClass.
For enhanced reuse, MetaProperties can be organized in a Pool and linked to many MetaClasses, using the Systemrelation MetaProperty
Data Types
A MetaProperty needs to have a data type that determines which kind of data should be stored in it. The following data types are supported by UBIK®:
Undefined
Boolean
A boolean value that can be either True or false
ByteStream
Source Code
A compressed text value, typically used to store texts with lots of white spaces and formatting information, such as source code.
Date/Time
Date and time in a combined value, where the actual format is depending on the cultural/regional settings of the machine.
Floating point
Double-precision floating-point format, optionally with unit of measurement that can be configured with the setting Unit item.
File reference
A path to a physical file in DOS/Windows- or UNC notation.
Geo Data
Absolute geographic position combined of Longitude, Latitude and Altitude in WGS84 format.
Guid
A pointer to another object, represented with the GUID of the target object.
Integer
An integer number.
Text
A string value.
XML
Markup text in XML format.
Configuration
A MetaProperty can be configured with various additional options which are described in the following.
String Length
Multilanguage
Reference
Selective List
Unit Item
Format
Value Validation
Needs Validation
Default value
The default value of a MetaProperty defines which value will be delivered by a property if it doesn't have an own value set.
Initial value
The initial value of a MetaProperty defines which value will be set to the property initially when a new instance of it is created. Once the value is changed, the initial value is lost for this instance.
Index Keys
Index Count
Index Type
Bytestream Type
Category
Editing a MetaProperty
Once a MetaProperty is used on a single MetaClass editing of properties is restricted to properties that may not effect data validity. The System uses a Rule to validate the edited properties and creates a RuleViolation whenever a "locked" property is edited. Following properties may not be changed/edited for a "used" MetaProperty:
- Name
- PropertyType
Released To LiveMode
A MetaProperty is marked as released to live mode when:
- It is used on at least one MetaClass which is already released.
- It is referenced by at least one PoolMetaProperty which is used on at least one MetaClass which is already released.
Editing a released MetaProperty is restricted to properties that have no effect on the released table structure. The System uses a Rule to validate the edited properties and creates a RuleViolation whenever a "locked" property is edited. Following properties may not be changed/edited for a released MetaProperty:
- Name
- PropertyType
- StringLen
- Multilanguage
- Indexcount
- Serialize
- NeedsValidation
- IndexType
