ConceptBase Tutorial
Contents
1. Add the BossRule to the database 3 4 Adding Integrity Constraints The following integrity constraint specifies that no Manager should earn less than 50000 Manager with constraint earnEnough forall m Manager x Integer m salary x gt x gt 50000 end Please note that our example model doesn t satisfy this constraint because Eleonore earns only 20000 If you use 20000 instead of 50000 the model satisfies this constraint and adding it will be successfull Figure shows the Telos editor after the attempt to tell the above integrity constraint The error message is shown in the error window Exercise 3 8 Define an integrity constraint stating that no employee is allowed to earn more money than any of her his bosses The constraint should work on each individual salary not on the sum In the subdirectory RULES CONSTRAINTS of the example directory there is a more extensive example concerning deductive rules and integrity constraints It should be used in addition to this section of the tutorial 3 5 Defining Queries In ConceptBase queries are represented as classes whose instances are the answer objects to the query The system internal object QueryClass may have so called query classes as instances which contain necessary and sufficient membership conditions for their instances Exercise 3 9 Load the object QueryClass into the Telos Editor window The syntax of query classes is a class definiti2. ConceptBase are welcome Contact us via http conceptbase cc 11 4 Solutions to the Exercises 2 1 Enter in the same command window the following command cbhserver port 5544 d TutDB You can also use the option db instead of d cbhserver port 5544 db TutDB In this case ConceptBase will maintain the Telos source representation of all objects in the database directory TutDB Your own definitions will go to the file System oHome sm1 because that is the default database module when you log into a ConceptBase server An alternative to starting the ConceptBase server from the command line is to start it from CBlva To do so start CBIva and the select the menu item File Start CBserver A window like in figure 3 will pop up and you need to change the following parameters 1 The port number could be changed to 5544 but you can also leave it to 4001 2 Enter the path of the database TutDB it is sufficient to replace the last two characters db by TutDB But remember the whole directory path 3 Change source mode to on This is equivalent to the db option above 4 Change update mode to persistent Then press OK to let CBlIva start a ConceptBase server with the specified parameters and connect to it Start CBserver Parameters Port 4001 Database Ime jeusfeld TutDB Source Mode on Trace Mode minimal v Update Mode persistent v Untell Mode cleanup v Multi user Mode disabled v Predicate Typing
3. because it is referenced in Bosses WithSalaries This query returns the instances of AllBosses together with their salaries Attributes of the category re trieved_attribute must be attributes of one of the superclasses of the query class In this example Boss esWithSalaries is a subclass of AllBosses which is subclass of Manager which is subclass of Employee The Employee class contains the declaration of the attribute salary So the retrieved attribute is permitted for BossesWithSalaries Exercise 3 10 Add the query class BossesWithSalaries to the database Query classes can also define computed_attributes These attributes are defined for the query class itself but unlike as for retrieved attributes they do not occur in the definition of the superclasses of the query class They are called computed because their computation is done during evaluating the constraint at runtime Computed_attributes don t exist persistently in the database that s why they don t get a persistent attribute label Instead the labels of the computed attributes of the answer objects are system generated CBiva ConceptBase cc User Interface in Java File Edit Browse Options History Windows Help BOMEeS Shae E Telos Editor Lloyd in BossesWithSalaries with salary LloydsSalary 100000 lend Phil in BossesWithSalaries with salary P
4. 8 Employee with constraint salaryIC forall e Employee m Manager x y Integer e boss m and e salary x and m salary y gt x lt y end 3 11 QueryClass BossesAndEmployees isA Manager with computed_attribute emps Employee head_of Department 15 constraint mployee_rule head_of head this and emps dept head_of end Figure 6 shows parts of the answer to the query BossesAndEmployees c ConceptBase cc User Interface i File Edit Browse Options History Windows Hel Bo a ane e E Display Quel F Telos Editor Select one Lioyd in BossesAndEmployees with emps COMPUTED_emps_id_1666 Michael head_of COMPUTED_head_of_id_1632 Production Phil in BossesAndEmployees with emps COMPUTED_emps_id_1682 Herbert head_of COMPUTED_head_of_id_1640 Marketing end Eleonore in BossesAndEmployees with emps COMPUTED_emps_id_1674 Maria head_of COMPUTED_head_of_id_1636 Administration lend Albert in BossesAndEmployees with emps COMPUTED_emps_id_1690 Edward head_of COMPUTED_head_of_id_1644 Research end History Window 39 ASK Eoee Query successful Version Now Module oHome 11 59 UTC 0 041 Figure 6 Display of answers of BossesAndEmployees 3 12 Select the option Stop CBserver from the File menu of CBIva Afterwards stop CBlva v
5. ConceptBase Tutorial Ren Soiron ConceptBase Team Informatik V RWTH Aachen Ahornstr 55 52056 Aachen Germany last update 2015 03 23 by Manfred Jeusfeld 1 Introduction This tutorial gives a beginners introduction into Telos and ConceptBase Telos is a formal language for rep resenting knowledge in a wide area of applications e g requirements and process modelling It integrates object oriented and deductive features into a logical framework ConceptBase is an experimental deduc tive database management system based on the Telos data model It is designed to store and manipulate a database of Telos objects The tutorial is organized as follows The next section gives a short introduction into the architectural organization of the ConceptBase system and describes the necessary steps to start the system Section three explains some basic features of Telos and ConceptBase using a simple example The last chapter contains solutions to the exercises Please note The objective of this tutorial is to give a novice user a first intuitive feeling on how to work with CB and how to build own models not to mention all the features of Telos and ConceptBase or describe the semantics of Telos 2 First Steps 2 1 Overview of the Architecture of the ConceptBase System ConceptBase is organized in a client server architecture The server manages the database while the client may be any user defined application program A graphical client CB va and
6. a resp cbiva bat in the installation directory of ConceptBase Exercise 2 2 Establish a connection between CBlva and the server you have started under 2 1 After the connection is established the first field of the statusline contains the status connected Note If your ConceptBase installation uses a public ConceptBase server then you can skip this step because your CBIva window automatically connects to the public server 3 The Example Model In this section the use of basic tools and concepts will be illustrated by modelling the following simple scenario A company has employees some of them being managers Employees have a name and a salary which may change from time to time They are assigned to departments which are headed by managers The boss of an employee can be derived from his department and the manager of that department No employee is allowed to earn more money than his boss The model we want to create contains two levels the class level containing the classes Employee Manager and Department and the token level which contains instances of these 3 classes 3 1 Editing Telos Objects 3 1 1 The Class Level The first step is to create the three classes used Employee Manager and Department Enter the following definition into the CBIva s top window labelled Telos Editor Employee in Class end This is the declaration of the class Employee which will contain every employee as instance Employee i
7. a command line client CBShell are distributed with the ConceptBase system We use in this tutorial the grahical client The communication between server and client is realized via Internet protocols i e client and server can run on different computers in your local network or even ob the global Internet They can also run on the same computer which is the most frequent way of use The connection is offered by the ConceptBase server via a so called port number Every database is stored in a seperate directory with the name of the database as directory name Before working with this tutorial ConceptBase has to be installed properly This is documented in the installation guide which is available from the site where you downloaded the system typically http conceptbase sourceforge net CB Download html 2 2 Starting the ConceptBase Server Skip this step if your ConceptBase installation is configured to use a public ConceptBase server in particular on Windows and Mac OS X At first start a ConceptBase server Exercise 2 1 a Get a description of all possible command line parameters by entering the following commands in a command window The commands are cd CB_HOME cbserver help The string SCB_HOME has to be replaced by the directory path into which ConceptBase was installed on your local computer You may want to include this directory path into the search path of your command shell b Start a ConceptBase server loadi
8. antiated the boss attribute of an employee The boss can be derived from the department the employee is assigned to and the head of this department So its obvious to define the instances of the boss attribute by adding a rule to the Employee Frame At first we ll give a short introduction into the syntax of the assertion language The exact syntax is given in the appendix of the user manual A deductive rule has the following format forall xl cl x2 c2 xn cn lt Rule gt gt lit al am where lt Rule gt is a formula and the xi s are variables bound to the class ci lit is a literal of type 1 or 3 see below and the variables among the ai s are included in x1 xn To compose the formula defining a deductive rule or integrity constraint the following literals may be used l x in c The object x is an instance of class c 2 c isA d The object c is a specialization subclass of d 3 x 1 y The object x has an attribute to object y and this relationship is an instance of an attribute category with label 1 Structural integrity demands that the label 1 belongs to an attribute of a class of x In order to avoid ambiguity neither in and isA nor the logical connectives and and or are allowed as attribute labels The next literals are second class citizens in formulas In contrast to the above literals they cannot be assigned to classes of the Telos database Consequently they may only be used f
9. enu items will open the Create Object dialog where you can specify new objects that should be created in the database Note that these modifications are not performed directly on the database The editor will collect all modifications and send them to the ConceptBase server when you click on the Commit button Delete object from database This operation will delete the object from the database As for the insertion of objects before the modification will be send to the server when you click on the Commit button Note that this operation has an effect on the database in contrast to the next operation Remove object from view The object will be removed from the current view This operation has no effect on the database i e the object will not be deleted from the database Display in Workbench This operation will load the frame of the object into the Telos editor Show in new Frame A new internal window within the Graph Editor will be shown and the selected object will be shown in the new window Exercise 3 6 Start a GraphBrowser and load Employee as initial object and experiment with the menu options avail able 3 3 Adding Deductive Rules At this point you should have made some experiences with the editing and browsing facilities of the ConceptBase Usage Environment and the Telos language This chapter gives an introduction into the use of rules and integrity constraints Until now we have never inst
10. hilsSalary 120000 lend Eleonore in BossesWithSalaries with salary EleonoresSalary 20000 end Albert in BossesWithSalaries with salary AlbertsSalary 110000 lend Telos Edita rHistory Window Version Now Module oHome 11 59 UTO 0 043 Figure 2 Result of asking the query BossesWithSalaries Figure 2 shows the Telos editor after asking the query BossesWithSalaries The following query class computes for every manager the department that he or she leads QueryClass BossesAndDepartments isA Manager with computed_attribute head_of Department constraint head_of_rule head_of head this end Exercise 3 11 10 Define a query class BossesAndEmployees which is a subclass of Manager and will return all leaders of departments with their department and the employees who work there More information about query classes can be found in the User manual chapter 2 3 and in the example directory QUERIES Exercise 3 12 Stop the ConceptBase server and the user interface This last step completes the tutorial We hope that it provided a first impression on ConceptBase and Telos Refer to the other examples especially to RULES CONSTRAINTS and QUERIES and of course to the user manual to learn more about the features of ConceptBase There is also a more advanced tutorial available on metamodeling Any comments and suggestions concerning this tutorial or
11. ia the Exit option in the same menu If you started the ConceptBase server with the db option or with source mode set to on then you find the sources of your definitions also in the directory TutDB see file System oHome sml1 Open this file with a text editor such as WordPad 16
12. ibute may contain several instances of this attribute Example George in Employee with name GeorgesName George D Smith salary GeogesBaseSalary 30000 GeorgesBonusSalary 3000 end The attribute dept and boss have no instances while salary is instantiated twice To complete the token level we have to add more employees to the database Exercise 3 5 Add the following employees to the database Use MichaelsDepartment etc as labels for the attributes employee department salary Michael Production 30000 Herbert Marketing 60000 Maria Administration 10000 Edward Research 50000 Now the first step in building the example database is completed The next chapter describes a basic tool of the usage environment which can be used for inspecting the database the GraphBrowser 3 2 The Graph Editor To start the Graph Editor choose the menu item Browse from the Workbench and select Graph Editor The Graph Editor will start up and establish a connection to the same server as the workbench if the workbench is currently connected You can establish additional connections from within the Graph Editor application If the Graph Editor has established the connection and loaded the initial data note this takes about 10 seconds you can add an object to the editor window by clicking on the Load object button An interaction window appears asking for an object name After entering a valid name e g Em
13. nager end Production in Department with head head_of_Production Lloyd end Administration in Department with 13 3 5 head head_of_Administration Eleonore end Marketing in Department with head head_of_Marketing Phil end Research in Department with head head_of_Research Albert end Lloyd in Manager with salary LloydsSalary 100000 end Phil in Manager with salary PhilsSalary 120000 end Eleonore in Manager with salary EleonoresSalary 20000 end Albert in Manager with salary AlbertsSalary 110000 end Michael in Employee with dept MichaelsDepartment Production salary MichaelsSalary 30000 end Maria in Employee with dept MariasDepartment Administration salary MariasSalary 10000 end Herbert in Employee with dept HerbertsDepartment Marketing salary 14 HerbertsSalary 60000 end Edward in Employee with dept EdwardsDepartment Research salary EdwardsSalary 50000 end 3 6 Figure 5 shows the ConceptBase graph editor on object Employee The attributes of Employee and its instances are expanded using the menu of the right mouse button clicked on Employee CB_GraphEditor File Edit Options View Current connection EF SIE ga Re E Create DE Fd PL R L LE Bd F localhost4001 222252 Connected with localhost Figure 5 CB Graph Editor on object Employee 3
14. ng the database TutDB on port number 5544 A server will start running immediately If the database TutDB doesn t exist a new database will be created before loading Then the copyright notice and parameter settings are displayed followed by a message which contains hostname and port number of the ConceptBase server you have just started These two informations are used to identify a server The host is the one you are currently logged on to and the port number is set by the port parameter The port number must be free on the host where ConceptBase shall run If this number is already in use by another server the error message IPC Error Unable to bind socket to name appears and the server stops In this case restart the server with another port number 2 3 Starting the ConceptBase User Interface Clients can communicate with a server through the ConceptBase Usage Environment The interface con tains several tools which can be invoked from the CB va ConceptBase User Interface in Java Start CBIva by entering the following commands in a new command window cd CB_HOME cbhiva After a few seconds a window will appear which is titled CBlIva ConceptBase User Interface in Java It consists of a main window statusline at the left buttom and offers several function keys and menu items A complete description of these menus is given in the User Manual Depending on your operating system you can also double click the file cbiv
15. nt and Manager of category attribute with label head at the class level Now we have to establish a link between Production and Lloyd of category head at the token level The label of this link must be a unique name for all links with the source object Production We choose head_of_Production as name The resulting Telos frame is Production in Department with head head_of_Production Lloyd end Exercise 3 4 a Add the frames for Lloyd Phil Eleonore and Albert to the database b Add the Telos frames for Production Marketing Administration and Research and the links between the departments and their manager to the database c The four managers have the following salaries manager salary Lloyd 100000 Phil 120000 Eleonore 20000 Albert 110000 Add this information to the database Use LloydsSalary PhilsSalary etc as labels Remember that you can load an existing object from the database into the Telos Editor by using Load frame The destination objects of attribute instantiations must be existing objects in the database or instances of the system builtin classes Integer Real or String Objects which instantiate these classes are generated automatically when referenced in a Telos frame At this point it is important to recognize that attributes specified at the class level do not need to be instantiated at the instance level On the other hand an instance of a class containing an attr
16. on with superclasses attributes and a membership condition The set of possible answers to a query is restricted to the set of common instances of all its superclasses The following query computes all managers which are bosses of an employee QueryClass AllBosses isA Manager with constraint all_bosse_srule exists e Employee e boss this end CBiva ConceptBase cc User Interface in Java File Edit Browse Options History Windows Help Bosses ANAA a Telos Editor Manager with constraint earnEnough forall m Manager x Integer m salary x gt x gt 50000 end 11 57 UTC 0 274 Figure 1 Telos Editor after the attempt to tell the integrity constraint The predefined variable this in the constraint is identified with all solutions of the query class Enter this query into the editor window and press Ask not Tell The query will be evaluated by the server and after a few seconds the answer will appear both in the protocoll and in the editor window If an error has occured and the query was typed correctly load the Employee frame and check if the frame contains the BossRule defined in chapter 3 3 If the answer was correct we add the query class AllBosses to the database The next query uses this query class to restrict the range of the answer set QueryClass BossesWithSalaries isA AllBosses with retrieved_attribute salary Integer end Before this Query can be evaluated AllBosses must be told
17. or testing i e in a legal formula their parameters must be bound by one of the literals 1 3 4 x lt y x gt y x lt y x gt y x y x lt gt y Note that x and y must be instances of Integer or Real 5 x y The objects x and y are the same You can also use x y and and or are allowed as infix operators to connect subformulas Variables in formulas can be quanti fied by forall x corexists x c where c is a class i e the range of x is the set of all instances of the class c The constants appearing in formulas must be names of existing objects in the database or of type Integer Real or String Also for the attribute predicates x 1 y occuring in the formulas there must be a unique attribute labelled 1 of one class c of x in the database For the exact syntax refer to the appendix of the user manual We ll give a first example of a deductive rule by defining the boss of an employee Employee with rule BossRule forall e Employee m Manager exists d Department e dept d and d head m gt e boss m end Please note that the text of the formula must be enclosed in and that this deductive rule is legal because all variables appearing in the conlusion literal e m are universally forall quantified The logically equivalent formula forall e Employee m Manager d Department e dept d and d head m gt e boss m can also be used Exercise 3 7
18. ow you have added attributes to the class Employee They are of the category attribute and their labels are name salary dept and boss They establish links between the class Employee and the classes mentioned as targets Department and Manager are user defined classes while String and Integer are builtin classes of ConceptBase Notice that these attributes are also available for the class Manager because this class is a subclass of Employee i e Telos offers attribute inheritance see also chapter 2 1 of the User manual Specialization axiom Exercise 3 3 The class Department has only one attribute the manager who leads the department Add this attribute to the class Department The label of this attribute shall be head Now we have completed the class level of our example The next step is to add instances of our classes to the database 3 1 3 The Token Level The company we are modelling consists of the 4 departments Production Marketing Administration and Research Every employee working in the company belongs to a department The employees will be listed later apart from the managers of the departments department head Production Lloyd Marketing Phil Administration Eleonore Research Albert 3 1 4 Defining Attributes of Tokens At first let s have a look at the department class defined in exercise 3 3 Department in Class with attribute head Manager end There is a link between Departme
19. ployee the Graph Browser displays the corresponding object By clicking the left mouse button every displayed object can be selected A selected object can be moved by dragging the object with the left mouse button pressed By clicking on the right mouse button a popup menu will be shown with the following operations Toggle component view switches the view of this object In the detailed component view you can either see the frame of this object or tree like representation of super and subclasses instances classes and attributes of this object Super classes sub classes classes instances for each menu item you can select whether you want to see only the explicitly defined super classes or sub classes etc or all super classes including all implicit relationships The query to the Con ceptBase server to retrieve this information will be done when you select the menu item So the construction of the corresponding submenu might take a few seconds Incoming and outgoing attributes The Graph Editor will ask the ConceptBase server for the attribute classes that apply to this object For each attribute class it is possible to display only explicit attributes or all attributes as above The attribute class Attribute applies for every object and all attributes are in this class Therefore all explicit attributes of an object will be visible in this category Add Instance Class SuperClass SubClass Attribute Individual These m
20. s declared as instance of the system class Class because it is on the class level of our example i e it is intended to have instances To add this object to the database press the Tell button If no syntax error occurs and the semantic integrity of the database isn t violated by this new object it will be added to the database The next class to ad is the class Manager Managers are also employees so the class Manager is declared as a specialization of Employee using the keyword isA Manager in Class isA Employee end Press the Clear button to clear the editor field Enter the telos frame given above and add it to the database by telling it The final class to be added is the class Department Exercise 3 1 Define a class Department and add it to the database At this point we have added some new classes to the object base but have told nothing about the so called attributes of these classes The modification of the classes we have just entered is the next task 3 1 2 Defining Attributes of Classes As mentioned in the description of the example model the employee class has several attributes To add them we need to modify the Telos frame describing the class Employee Exercise 3 2 Load the object Employee via the load frame button and modify it as follows Employee in Class with attribute name String salary Integer dept Department boss Manager end Tell the modified Employee frame to the database N
21. strict v Cache Mode keep v ECA Mode safe v Figure 3 Start CBserver from CBIva 2 2 Select Connect from the File menu An interaction window appears querying the host name and the port number of the server you want to connect to Enter the name of the host the ConceptBase server was started on and the port number specified by the p parameter then select Connect If you started the ConceptBase server on the same computer as CBIva then use localhost as hostname This step is obsolete if you started the ConceptBase server from within CBIva 12 3 1 Department in Class end 3 2 To load an object from the database into the editor window select the frame button with tooltip 3 3 3 4 Load an object from CBserver of the button panel or the option Load Object from the Edit menu You should have a similar view as displayed in figure 4 CBiva ConceptBase cc User Interface in Java File Edit Browse Options History Windows Help Te te oi 2 Employee in Class with attribute name String salary Integer dept Department boss Manager end History Window meea Connection established Version Now Module oHome 8 46 UTC 0 00s Figure 4 CBlIva Telos Editor Department in Class with attribute head Manager end Lloyd in Manager end Phil in Manager end Eleonore in Manager end Albert in Ma
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