Abstract:
A computer program product is provided as a system and associated method that allows the user to view a hierarchical lineage in a tree format even in the event of recursive circular relationships. The system prevents the lineage tree from being infinitely expandable truncating tree expansion when encountering a child that has previously appeared in the tree. If the user attempts to expand on an object that leads to a child already displayed in the tree, the system replaces the child&#39;s icon with one that resembles a recursive icon. The recursive icon is displayed by the system at the point of recursion, showing that an infinite, recursive relationship has occurred.

Description:
FIELD OF THE INVENTION 
   The present invention relates in general to user-interactive computer supported displays, and particularly to a user-interactive system and method that provide interactive users with a user-friendly interface for accessing lineage tree displays used in queries and data warehousing applications. The system of the invention provides a method for displaying objects in a lineage tree even if recursive elements in the tree exist, allowing the lineage tree to be automatically expanded even if a recursive node exists. 
   BACKGROUND OF THE INVENTION 
   Businesses and consumers exert a continuing demand on the consumer electronics industry for improvements in computer and network display interfaces for accessing functions and data from the computer. Businesses demand interfaces that are quickly learned by their existing workforce while consumers require interfaces that are easily understood and mastered. In the area of database management and data warehousing, interfaces to the databases appear to be formidable obstacles to many users who would have considerable needs for data access. Historically, database management was one of the primary computer functions; consequently, it is based on language and functions developed by computer professionals that are not accessible to the average employee or consumer. As a result, data management and access may be somewhat esoteric and foreboding to new computer users in the business and personal computer situations that would most benefit from the development of and access to databases. 
   One particular hurdle for database comprehension is that the average computer user finds it very difficult to frame database search queries out of the relatively complex SQL language used by many databases. In addition, once the query is formed, display of the results can be difficult to interpret and manage when it includes recursive relationships between objects. Query results that include object relationships are typically presented to the user graphically as a hierarchical display called a tree format. Using a tree format, the Lineage tree window displays objects that are related as input or output to data transformers and data resources. This allows the lineage or heritage of how a data resource is built to be traced backwards. The lineage tree function is used primarily for warehouse center metadata that describes tasks and data resources and the relationships between them. A lineage tree as displayed by the computer consists of a root and children; the lineage tree function is applied to the root, producing objects that are the “children”. 
   A tree view is advantageous for displaying relationships between objects because it allows the user to expand on objects, displaying the children contained within the tree. Due to its graphical representation, results returned in a tree view are relatively easy to interpret. However, tree views present certain shortcomings for conventional design applications. One disadvantage is the manner in which the display manages recursive relationships, ones that have as children an object currently displayed above as an ancestor in the tree. In standard database applications using tree views for graphical interface, the existence of a recursive relationship could cause the lineage tree to expand infinitely. Should the user decide to expand the entire tree, the computer system could encounter a memory constraint problem, leading to significant waste of precious CPU time, an inability to automatically expand the tree, and difficulty in finding objects as the view becomes cluttered with repetitive information. 
   Thus, there is need for a system which displays results of objects with recursive relationships in an easy to understand graphical format that also prevents the user from engaging the problems inherent in recurrent branches and relationships. The need for such a system has heretofore remained unsatisfied. 
   SUMMARY OF THE INVENTION 
   The system and method for displaying a recursive relationship between objects in a tree satisfies this need. This invention describes a system and method that allows the user to see a hierarchical lineage in a tree format even in the event of recursive circular relationships by preventing the lineage tree from being infinitely expandable. The system of the invention truncates tree expansion when encountering a child that has previously appeared in the tree. The system of the invention provides an effective, user-friendly, GUI-based solution involving the display of a “recycle” icon. If the user attempts to expand on an object that leads to a child already displayed in the tree, the system of the invention replaces the child&#39;s icon with one that resembles a recycling metaphor. The “recycle” icon is displayed by the system of the invention at the point of recursion, showing that an infinite, recursive relationship has occurred. 
   The present invention prevents the waste of computer memory due to infinitely expanding trees and excessive consumption of CPU time spent performing queries within circular relationships. Among the features of the present system are: a) the recycling icon (or recycling metaphor which is posted at the truncation of infinitely recursive branches and b) the “Expand all” command which automatically expands the entire tree with the click of a button. Without the introduction of the “recycle icon” as a substitute for recursive branches, automatic expansion of the entire tree would not be possible. The introduction of these two features greatly enhances the ease of use for the typical user. The user does not have to expand the tree step-by-step, and any recursions in the tree can be seen without incurring computer system problems with memory or CPU resources. This allows the average user more power and flexibility in developing and analyzing database queries. The user does not have to carefully plan each query to preclude the display of recursive branches. In addition, the user can easily see the objects and nodes on the tree because the lineage tree display isn&#39;t cluttered with many repeating branches. 
   The system of the invention also maintains for each query display a list of objects that appear in the query response tree. This list of objects is referenced by the system when adding a new object to the tree. If the object is “recursive” (i.e, found in the list) the system adds a recycle icon to the parent object and the recursive object is not displayed. By eliminating the possibility of displaying recursive objects, the system of the invention renders data warehouse manipulations more effective. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The various features of the present invention and the manner of attaining them will be described in greater detail with reference to the following description, claims, and drawings, wherein reference numerals are reused, where appropriate, to indicate a correspondence between the referenced items, and wherein: 
       FIG. 1  is a schematic illustration of an exemplary operating environment in which a recursive relation display system of the present invention displays a recursive relationship between two trees system; 
       FIG. 2  portrays an example Show Lineage Tree window (or screen shot) in accordance with the operation of the system of the present invention; 
       FIG. 3  illustrates an expanded tree view of the example of  FIG. 2 ; 
       FIG. 4  illustrates an example of a recursive complication in an expanded tree view; 
       FIG. 5  illustrates the “Expand All” function; 
       FIG. 6  is a flow chart illustrating the logic of a preferred embodiment of the present system; and 
       FIG. 7  illustrates a window that exemplifies the performance of the present system. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   The following definitions and explanations provide background information pertaining to the technical field of the present invention, and are intended to facilitate the understanding of the present invention without limiting its scope: 
   Data Warehousing: an all-encompassing term for a system that stores, retrieves and manages sizeable amounts of many types of data. Typical data warehouse software employs complex steps or programs to manipulate data into formats needed for more advanced operations or analysis. Data warehousing may also comprise a remote database holding current snapshots of corporate data. Researchers and developers utilize the data targets produced though warehousing steps without slowing daily operations of the production database. 
   Internet: A collection of interconnected public and private computer networks that are linked together with routers by a set of standards protocols to form a global, distributed network. 
   SQL: Structured Query Language, a standardized query language for requesting information from a database. 
   Metadata: data about data. Metadata is definitional data that provides documentation of or information about other data managed within an environment or by an application. Metadata may document data about data elements or attributes such as name, size, or data type. It may also log data about data structures including length, fields, and columns. Other data included in Metadata encompass the association, storage location, and ownership of data. Metadata may additionally include descriptive information about the context, quality and condition, and/or characteristics of data. 
     FIG. 1  portrays the overall environment in which a method for displaying a recursive relationship between objects in a tree system  10  according to the present invention may be used. The system  10  includes a software or computer program product that is typically embedded within, or installed on a client machine  15 . Alternatively, the display system can be saved on a suitable computer usable medium such as a diskette, a CD, a hard drive, or like storage devices. While the display system will be described in connection with query searches, the display system can be used with a stand-alone machine with a local database of documents or other text sources that may have been derived from the WWW (World Wide Web) or other sources. 
   The cloud-like communication network  20  is comprised of communication lines and switches connecting servers to gateways. The servers and the gateways provide the communication access to the WWW Internet. Users, such as remote Internet users (or clients) are represented by a variety of computers such as computers  15 ,  125 ,  130 , and can query a database or file server  111  for the desired information. The display of the information is rendered on the users machines such as computers  15 ,  125 ,  130 . Though one recursive relation display system  10  is shown connected to one client computer  15 , which system  10  is readily accessible by the other remote client computers  125 ,  130 , it should be clear that each of these remote client computers  125 , 130 , could be provided with a dedicated (or shared) recursive relation display system  10 . 
   The client machine  15  is connected to the network  120  via a communications link  115 , such as a telephone, cable, or satellite link. The servers in the network  120  can be connected via high speed Internet network lines to other computers and gateways. The servers provide access to stored information such as hypertext or web documents. The hypertext documents most likely include embedded hypertext link to other locally stored pages, and hypertext links to other webs sites or documents that are stored by various web servers. 
   The system  10  graphically displays a tree hierarchy as shown by the “show lineage tree” window  205  in FIG.  2 . In window  205 , the lineage tree function displays the objects and functions that either lead to the data found in data resource  210  or are passed through a data transformer such as node  215 . For example, data resource  210  represents a table labeled “Department” which is the root of the tree  220 . Node  215  represents the task “Cleanse Data”, while data resource  210  represents an address location of the table “Department” which is the output target from the task at node  215 . The “+” symbol at node  215  indicates that there are hierarchical or precedence relationships within this object. Clicking the “+” symbol expands a parent node into at least one child node. Though specific symbols, such as “+” and “−” are used herein as exemplary symbols, it is clear that other symbols could alternatively be used to perform the same or similar functions. 
   The lineage tree  220  of window  205  is displayed in  FIG. 3  in a partially expanded tree  305 . The “cleanse data” node  215  represents a task that is responsible for data extraction, transformation, and loading into the data resource  210 . Data resource  310  is the input source table labeled “Old Department” that was processed by the “cleanse data” node  215  to create output target data resource  210 . Clicking the “−” symbol at node  215  collapses tree  305 , reverting to the tree  220  displayed in FIG.  2 . 
     FIG. 4  illustrates through an expanded tree view the complications in displaying lineage trees with recursive branches. As seen in  FIG. 4 , the nodes  405 ,  410 ,  415 ,  420  are objects that are returned as a result of a query. Object  405  is the main parent node in this tree, similar to data resource  210  in FIG.  2 . Object  410  is the child of the parent object  405  and the parent of child object  415 . Object  415  is simultaneously the child of object  410  and the grandchild of object  405 . Similarly, object  420  is the child of object  415 , the grandchild of  410 , the great-grandchild of  405  as well as the parent of object  405 . At object  420 , the tree view starts to infinitely expand in a recursive branch, presenting a graphical display challenge to the traditional lineage tree. 
   The system  10  of the invention solves the problem of recursive branches in a graphical display of hierarchical trees by inserting a “recycle” icon at the point the recurring branch occurs.  FIG. 5  shows window  205  with the expandable tree  220 . The user selects pull-down menu item  505 . The use of an icon to represent a recurring branch enables the system  10  to provide the “expand all” feature  510 . Data resource  210 , “Department”, is the root of the tree  220 . The “+” at node  215  indicates that there are hierarchical relationships within the node  215  labeled “Cleanse Data”. The user may click on the “+” at node  420  to expand this parent node into children nodes. Alternatively, the user may select the view pull-down menu  505  that offers the user a choice to either automatically collapse all nodes or automatically expand all nodes in the tree  220 . As seen by the highlighted background, the user selects the “Expand all” option  510 , selecting automatic expansion of the tree. This feature of the invention expands the tree in its entirety. If a repeating node is part of the tree  220 , the system  10  truncates the recurring branch at the object closest in hierarchy to the repeating node and a “recycle” icon terminates the branch. 
   The logic of the preferred embodiment of the invention is described by the flowchart of FIG.  6 . In operation, and with further reference to the example of  FIG. 7 , the user opens the show lineage tree window  205  in step  605  to display the first data resource  210  and task node  215  in the lineage tree  705 . System  10  checks to determine if the first child node  215  involves a recursive process at step  610 . If so, the system  10  inserts a recursion icon at step  615 , selects the recursion icon at step  620 , and sets that node as a “last node”. If the user double clicks the recursion (or recycle) icon, then the selection is returned to the node preceding the recursive node in step  625 . If the first step is not recursive, then system  10  proceeds to step  630  and expands the node. 
   There are two methods for expanding any tree: manual expand and auto expand. In the case of  FIG. 7 , auto expand has been selected. If system  10  detects a request for auto expansion in step  635 , system  10  examines all nodes in the lineage tree  705  in step  640 , comparing each node with a list of nodes maintained by system  10  for the lineage tree  705 . Any duplicate objects in the list of ancestor nodes are recurring objects. If system  10  detects a recurring node at step  645 , the system inserts a recursion icon at the point of recursion in step  615 , sets the recursion icon for the object at that point in step  625 . 
   In the example of  FIG. 7 , the first object is data resource  210 . The first task is at node  215 , “cleanse data”. The source for data resource  210  is data resource  215  “old department”. In examining the list of ancestor nodes in step  640 , system  10  finds that the following task Cleanse Data  2  ( 715 ) has a relationship to data resource Department ( 210 ) making a circular loop. System  10  replaces this recursive branch in step  615  by inserting a recursion recycle icon for “Cleanse Data  2 ”  715 , Double clicking on the recursion (or recycle) icon in step  620 , will select the preceding connecting node in step  625 . All other nodes have been expanded automatically, so the tree display continues at data object  710  with data resource  720  “Temporary Target”. The rest of the lineage tree  705  has no recursive elements. If there are no duplicate nodes on the lineage data list, system  10  proceeds to step  650 , expanding the tree and ends expansion at step  655 . All nodes in tree  705  are now displayed in the expanded format as shown by the “−” symbol at the expansion nodes, typified by nodes  215 ,  710 , and  720 . To collapse a node, the user may click on the “−” at a node such as node  215 . The tree will be truncated at that point and the “−” will be replaced by a “+”, indicating that the tree is not fully displayed and can be expanded at that point. 
   It is to be understood that the specific embodiments of the invention that have been described are merely illustrative of certain application of the principle of the present invention. Numerous modifications may be made to the system and method for displaying a recursive relationship between objects in a tree invention described herein without departing from the spirit and scope of the present invention. Moreover, while the present invention is described for illustration purpose only in relation to the WWW and to search results, it should be clear that the invention is applicable as well to file systems or any other data or data system based on a hierarchical structure.