Case metadata
Mercury is a repository of metadata about objects along with definitions of GUI controls enabling the generation of GUI forms. Metadata is structured information used to describe objects (cases) - it describes the logical and physical relationship between parts of a complex object (see Describing digital objects, October 21, 2016 [accessed 2020-07-01]). Mercury DB in its structures also allows for storing the necessary data allowing for the generation of edit forms and presentation pages of stored objects. Metadata is stored in a relational database (SQL). A synonym for the definition of case metadata is the case type. Below is a description of the entity.
Case versioning
When updating case objects, the change history is automatically created. However, when the case type changes, which is often the case in rapidly developing systems that change the data storage model, a new version of the case is created. The action occurs automatically when (using business layer services) we save the case (existing) and when a type change is detected, i.e. a new field is added, a field type change is detected. Since version 3.0.1.0.2, the version change action can be performed "manually" by invoking the appropriate sequence of saves, which we will discuss at the end of the article.
Index Lucene
The basis for searching in the Mercury DB system is the [Lucene] Index (https://lucene.apache.org). This article will present the principles of creating field names, which are the basis for implementing search queries. It will also present the division of fields according to their type, category (division according to field origin) and search method (division according to field type).