This manager is an abstract component, extensions of which are used for several different purposes in the system. The main function of this component is to maintain a set of entities, their storage and retrieval. This component supplies an environment where the user can arrange the entities in logical unions, which in turn, give better management capabilities for the data. Here the hierarchical model is exploited intensively.
The Entry Manager is used in three important components in the system:
Each Entry Manager represents a set of repositories, called Corpora which contain the corresponding entities. The different corpora are identified by unique (user supplied) names. Each corpus contains a set of entities which are stored independently from the entities of other corpora. No entities can be saved outside a corpus. The entities within a corpus are identified by unique names, i.e. no two entities can have the same name. If it is necessary that two or more entities should share the same name, they must be stored in different corpora.
The possible operations on corpora are:
Corpora are entities containers only, so it is not possible a corpus to contain another corpus. Each corpus has its own internal logical structure which facilitates the maintenance of many entities at the same time. The entities within a corpus are organized in groups. Each group can contain a set of entities as well as a set of subgroups. Each group is identified by an unique name within the group in which it is included, but not necessary unique for the containing corpus. The supported operations on groups are: creating a new group or a subgroup of a group; renaming a group and removing a group. The user can include or exclude entries in/from a group.
The groups are logical unions of entities which do not impact physically the entities themselves. This means that if an entity is removed (excluded) from a group, the entity itself is not deleted from the database, but just excluded from this union. Thus the same entity can be included in more than one group, as well as an entity can be included in none.
Note: technically said, the groups contain not entities, but references to entities. In this way, if an entity is presented in more than one group, the entity itself is not multiplied for each containing group, but the single instance is referred by links from each group entry.
The Entry Manager offers three views on the data:
Here is one example picture of the Entry Manager window in By Groups mode:
The manager window consists of two main parts:
There are six additional buttons which can be used for
modification the content of the current group:
Navigation in the group structure can be made also in the panel on the right. When the user wants to see the content of a certain sub-group of the current group, s/he just has to perform a double click on the desired sub-group. This will change the current group to the new one. This represents the movement from a group to a sub-group. The movement in the other direction is also possible. For each entity group (excluding the corpus root), a special sub-group is included, named: ". .". By performing a double click on it, similarly to most file systems, the current group is changed to its parent one.
The Entry Manager also provides two additional views for the entries in a table form. The first one shows all entries included in a certain corpus. The second view shows all entries from all corpora in one table.
The following information appears for each entry: its name, the corpus it is included in, the time of the last modification, its DTD and some other specific information. For the documents in the internal documents database, if a document is a query, the corresponding tool name is shown.
The user can sort all the entries by clicking on a corresponding column header.
In these views, the right button of the mouse can be used for manipulation of the selected entries in the table. Having pressed the right mouse button, the following pop-up menu appears:
Here is one example picture of all entries in a corpus: