Classifications

• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06F—ELECTRIC DIGITAL DATA PROCESSING
  • G06F16/00—Information retrieval; Database structures therefor; File system structures therefor
  • G06F16/20—Information retrieval; Database structures therefor; File system structures therefor of structured data, e.g. relational data
  • G06F16/28—Databases characterised by their database models, e.g. relational or object models
  • G06F16/289—Object oriented databases

Definitions

• the present invention relates to a user interface for specifying index groups for classes for data stored in a database.
• a relational database stores data in tables having rows (records) and columns (fields).
• the tables are usually interrelated, and thus, there is a logical structure imposed on the database.
• This logical structure is known as a schema.
• Each table has a primary key, comprising one or more columns that uniquely identify a row. For example, in a table with rows of customers, a column storing each customer's social security number may be used as the primary key because it uniquely identifies each customer in the table.
• a table may also have another key, known as a foreign key, associating a row in one table to one or more rows in another table. For example, where one table contains customer information and another table contains order information for the customers, a foreign key may exist to relate one customer (or row) in the customer table with one or more orders (or rows) in the order table.
• Object-relational mapping tools read a database and automatically generate source code from the database.
• This source code contains a number of classes whose interrelationships reflect the logical structure, or schema, of the database.
• a class such as a JavaTM class, is a data structure containing both data members that store data and function members (or methods) that act upon the data.
• the source code contains one class for each table in the database, and each class has a data member for each column in the corresponding table. Additionally, the classes contain function members that are used to both get and set the values for the data members and, eventually, update the database.
• the programmer After the source code is generated, the programmer writes code to interact with the classes in the source code. This helps to hide the complexities of interacting with the database from the programmer. This allows a programmer who is familiar with object-oriented programming to code against familiar classes and not unfamiliar, sometimes cumbersome to use, database query languages.
• index refers to data included within a particular database and is used to permit faster retrieval of information from the database.
• Data in a column of a table is typically stored in random order, and locating a particular data element requires a search through each data element in the column.
• a system can more quickly locate and retrieve particular data elements.
• mapping tools do not enable users to specify indexes based on classes mapped from tables in a relational database. A need therefore exists for a mapping tool with this capability.
• Figure 1 depicts a data processing system suitable for practicing methods and systems consistent with the present invention
• Figure 2 depicts a more detailed diagram of the database depicted in Figure 1;
• Figure 3 depicts a database data structure reflecting the schema of the database depicted in Figure 1 ;
• Figure 4 A depicts an object model containing information derived from the database data structure depicted in Figure 3;
• Figure 4B depicts source code generated from the object model depicted in Figure 4A
• Figure 5 is a diagram of an exemplary index group for a field in an object
• Figure 6 is .an ex-ample of a user interface for permitting a user to define index groups over classes
• Figure 7 is a block diagram of software modules for accessing and operating on data in a relational database using index groups;
• Figure 8 is a diagram of software modules for processing transactions using index groups;
• Figure 9 is a flow chart of an exemplary process associated with the user interface shown in Figure 6.
• Apparatus and methods consistent with the present invention include providing a user interface to allow a programmer or other person to view and enter information relating to index groups, potentially for use with a mapping tool that maps corresponding data between a relational model and an object model.
• a method consistent with the present invention includes providing a user interface having information representing data in a database and storing a plurality of index groups associated with the data. Information representing one or more of the index groups is selectively displayed through the user interface.
• Another method consistent with the present invention includes providing a user interface having information representing data in a database and receiving through the user interface information for defining an index group associated with the data.
• the defined index group is stored for use in processing associated with the data.
• An apparatus consistent with the present invention provides a user interface having information representing data in a database and stores a plurality of index groups associated with the data. The apparatus selectively displays through the user interface information representing one or more of the index groups.
• Another apparatus consistent with the present invention provides a user interface having information representing data in a database and receives through the user interface information for defining an index group associated with the data. The apparatus stores the defined index group for use in processing associated with the data.
• Methods and systems consistent with the present invention provide a user interface for a user to specify index groups over classes of obj ects potentially mapped from a relational database.
• An "index group” refers to an identification data to be mapped to a database index.
• the interface may also be used to modify or delete existing index groups.
• An optional mapping tool maps the index groups during mapping of data between objects in .an object- oriented model and tables in a relational model and, therefore, a user's specified index groups are saved and need not be repeatedly recreated.
• the improved object-relational mapping tool maps a database by first querying the database to determine its schema and then by creating an internal data structure (known as the "database data structure") representing that schema. From this data structure, the object-relational mapping tool creates an object model containing all of the information necessary to generate classes and then creates source code containing a number of Java classes that may be used by a programmer to interface with the database.
• FIG. 1 depicts a data processing system 100 suitable for practicing methods and systems consistent with the present invention.
• Data processing system 100 includes computer 101 connected to network 102, such as the Internet.
• Computer 101 includes memory 104, secondary storage device 106, central processing unit (CPU) 108, input device
• Memory 104 includes an object-relational mapping tool 114 (ORMT) in accordance with methods and systems consistent with the present invention.
• the object-relational mapping tool 114 includes object model 116 and database data structure 115, reflecting the schema of database 118, stored on secondary storage device 106.
• source code 120 Also stored on secondary storage device 106 is source code 120, containing classes reflecting the schema of database 118 and containing any customizations of the programmer.
• Memory 104 also includes a runtime system 123, which includes a virtual machine (VM) 124.
• Secondary storage device 106 further contains a program 125 with source code .and various class files 126.
• An exemplary runtime system for purposes of implementing methods .and systems consistent with the principles of the present invention includes the JavaTM runtime system included in the JavaTM Development Kit from Sun Microsystems, Inc.
• the Java runtime system includes a Java VM.
• the Java VM is described in Lindholm and Yellin, The JavaTM Virtual Machine Specification. Addison- Wesley (1997), which is incorporated herein by reference.
• computer 101 is depicted with various components, one skilled in the art will appreciate that this computer can contain additional or different components. Additionally, although computer 101 is shown connected to network 102, computer 101 may be connected to other networks, including other wide area networks or local area networks. Furthermore, although aspects of the present invention are described as being stored in memory, one skilled in the art will appreciate that these aspects can also be stored on or read from other types of computer program products or computer-readable media, such as secondary storage devices, including hard disks, floppy disks, or CD-ROM; a carrier wave from the Internet; or other forms of RAM or ROM. Still further, one skilled in the art will appreciate that database 118 and source code 120 may be stored on or distributed across other devices on network 102. In addition, the computer-readable media may include instructions for controlling a computer systems, such as computer 101, to perform a particular method.
• Sun, Sun Microsystems, the Sun logo, JavaTM, and JavaTM-based trademarks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries.
• Object-relational mapping tool 114 reads database 118 to examine its schema, constructs database data structure 115 to reflect this schema, generates an object model 116 based on database data structure 115, .and then creates source code 120 based on obj ect model 116. It should be noted that, at the time object model 116 is generated, the object-relational mapping tool allows the programmer to add customizations, and these customizations will be reflected in the source code 120. For example, the progr-ammer may add a new method, rename a field (and use it for a different purpose), ch-ange the attributes of a field (e.g., the type or whether it can accept a null value), or override the mapping of a field.
• the progr-ammer may add a new method, rename a field (and use it for a different purpose), ch-ange the attributes of a field (e.g., the type or whether it can accept a null value), or
• FIG. 2 depicts a more detailed diagram of an example of database 118, containing a customer table 202 and an order table 204.
• the customer table 202 includes a customer ID column 206, and a name column 208.
• the customer ID column 206 serves as the primary key for the customer table 202.
• the order table 204 includes order ID column 212, date column 214, .and customer ID column 216.
• the order ED column 212 serves as the primary key for the order table 204.
• Customer ED column 216 is the foreign key to customer ED column 206, meaning customer ID column 216 refers to the customer ID column 206 in one or more rows.
• database data structure 115 represents the schema of database 118.
• Object-relational mapping tool 114 creates database data structure 115 by querying database 118 to identify its schema and by creating the data structure to reflect the schema.
• database data structure 115 appears as shown in Figure 3 .and includes an object 302, reflecting the customer table 202, and an object 304, reflecting the order table 204.
• Object 302 contains a list 306 of foreign key objects, if any, each containing the name of the foreign key as well as an indication of the columns that comprise the foreign key.
• object 302 contains a list 308 of the indexes in the customer table 202, where each element of the list is an index object containing an indication of the type of index (e.g., primary, non-unique, .and unique) and a list of columns that comprise the index.
• Object 302 also contains a hash table 310, where each entry in the hash table is a column obj ect 312, 314 containing data for a particular field, including its name, type, .and length.
• Object 304 contains similar information, including a list of foreign keys 316, a list of indexes 318, and a hash table 320 with column objects 322-326 for each field or column.
• the programmer may customize the object model. For example, the programmer may rename the name field to SSN and may subsequently use this field to store the customer's social security number, in which case the customer's social security number will be stored in the name field 208 of the database 118. By making such a customization, it is reflected in the object model 116 shown in Figure 4A.
• Object model 116 generated by the object-relational mapping tool, contains the programmer's customization (e.g., the name field has been renamed to SSN).
• Object model 116 contains objects 400 and 401, representing an intermediate form of the information for a class before it is written as source code.
• Object 400 contains information for the customer table 202, including a list 402 of relationship objects 403, each containing information indicating a relationship (i.e., a foreign key). For example, relationship object 403 links a field in object 400 with a field in object 401. Additionally, object 400 contains a hash table 404 with an entry 406, 408 for each field in customer table 202, each entry containing the name and type of the field. Similarly, object 401 contains information for order table 204, including a list 410 of relationship objects 411 and a hash table 412 containing entries 414- 418 for each field in order table 204.
• object model 116 contains all of the information necessary to create the classes in the source code, an example of which is depicted in Figure 4B.
• Figure 4B depicts source code file 116 with the JavaTM programming language representation of objects 400 and 401.
• Class 420 reflects customer table 202 and class 424 reflects order table 204.
• class 420 contains a data member for customer ID, social security number, .and a collection of objects representing the orders associated with that particular customer, thus implementing the foreign key.
• Class 420 also contains a number of methods to both get -and set the value of the data members, including an iterator method to iterate through the order for this p.articular customer.
• Class 424 includes data members order ID and date and also includes various methods to both set and get the values for these data members. Additionally, class 424 contains a field, Customer_for_Order, implementing the foreign key with a reference to the particular customer object that placed that order.
• the object-relational mapping tool When a foreign key is contained in the object model, the object-relational mapping tool typically creates a relationship in the source code between two classes to implement the foreign key.
• one or more records in one table (the referring table) refers to one record in another table (the referred table).
• This relationship is a one-to-many relationship, although it may be a one-to-one relationship. Additionally, instead of being bidirectional, the relationship may be unidirectional.
• the class representing the referring table is defined to have a member that is a collection of the class representing the referred table.
• a "collection" refers to a type indicating a grouping of instances of other classes.
• Figure 5 illustrates an example of an index group 502 for an object 500, which provides an example of an object for specifying information for customers.
• object 500 includes an identification field, a name field 501, and possibly other fields of data.
• Index group 502 corresponds to the entries within name field 501, and it provides an indication of data to be mapped to a database index for use in faster retrieval of information from the name field.
• the data elements in name field 501 are typically not stored in a particular order, meaning that each data element must be examined in order to locate a particular data element. Therefore, index group 502 provides a reference to a database index for faster data retrieval and more efficient data processing.
• index groups may include a set of fields, as defined by a user.
• An example of a database index is a b-tree, which is known in the art.
• An implementation consistent with the present invention does not depend upon any particular type of database index and may be used with any index or ordered method of storing data for retrieval.
• An implementation consistent with the present invention relates to a user interface for specifying and managing index groups over classes.
• a "user interface” refers to a mechanism to view a representation of information in a computer system, such as computer 101, .and to enter information into the computer system.
• the input information may include commands instructing the computer to perform a particular function.
• Figure 6 illustrates an example of such a user interface 600.
• Video display 112 may present user interface 600 in order to permit a user to view information relating to index groups, and a user may use input device 110, such as a cursor-control device, to enter or modify information through user interface 600.
• Index groups defined through user interface 600 are typically stored in computer 101 such as in memory 104 or secondary storage 106.
• the appearance and structure of user interface 600 are only one such example of a user interface for accomplishing functions relating to index groups, and implementations consistent with the present invention include any mechanism to display and enter information relating to index groups.
• index group tab 613 When a user selects index group tab 613, the user may enter and define index groups for particular classes, shown in a section 601.
• a "section” refers to an area of a user interface in which a system presents information or receives information from a user. The act of selecting may include using a cursor-control device to "click on” or “double click on” a particular item in the user interface.
• User interface 600 includes section 601 in order to illustrate fields of a particular class representing data in a database. A user may select the boxes next to the classes in order to expand the listing and view information related to each class, including fields of the class and index groups defined for the class. For example, a class Customer 615 is shown as having a number of fields 616 and as associated with one or more index groups 602.
• one index group new_item 603 is defined for class Customer 615.
• a section 604 presents the corresponding index group and a section 606 presents the fields of class Customer 615.
• a user may select other classes in section 601 in a similar manner, and fields for those classes are also presented in section 606 when corresponding classes are selected.
• a field 607 permits the user to enter a name or update a name for an index group
• a field 608 provides another section 609 permitting a user to select an identification of the index group as unique or non-unique.
• a unique index group is one in which no duplicate values may exist among the data elements in the index data structure, .and a non-unique index group is one which permits duplicate values. If a unique index group is defined over multiple columns or fields, no duplicates may exist in the combination; in other words, the combination of data elements in the selected columns or fields must be unique.
• a section 614 includes both section 604 for listing index group names and section 605 for identifying whether corresponding index groups are unique or non-unique. Sections 606 and 614 include scroll bars so that a user may scroll through index groups or fields if there is insufficient room to illustrate all the index groups or fields within the corresponding section.
• a user may perform functions on index groups by selecting buttons 610-612.
• a user may update a defined index group
• new button 611 a user may define and enter a new index group.
• a user selects the boxes next to the particular fields in section 606 in order to select or deselect those fields to include within the index group shown in section 604.
• a check mark appears in the box next to the field in section 606 to indicate its selection.
• the check mark disappears, indicating deselection of the corresponding field.
• Other types of indicators are possible for showing selection of a field, such as highlighting the field, displaying the field within a box or in a different color, or displaying some other type of icon next to the field.
• the user may also select a button within section 609 to identify the type of index group .as unique or non-unique, .and section 605 displays the selected type.
• a user may enter a name of a new index group or modify the name of a defined index group, and the entered name is shown in section 604.
• update button 610 When a user selects update button 610, the system saves the new index group or updates an index group according to the user's selections, and the new or updated index group is saved in the system .and presented within section 601 for the corresponding class.
• delete button 612 By selecting delete button 612, a user may delete a defined index group. In particular, a user first selects an index group in section 601 and then selects delete button 612, after which the system deletes that defined index group and removes it from section 601. Index Group Modules
• FIG. 7 is a block diagram of software modules for implementing the exemplary user interface shown in Figure 6. These modules may operate within the hardware elements shown in Figure 1.
• user interface 600 is typically part of a mapping tool 701 such as ORMT 114.
• Mapping tool 701 includes a relational model 702, an obj ect model 704, and a mapping engine 703 for converting data between the relational model and the object model.
• Relational model 702 stores a representation of data from database 707 in tables
• object model 704 stores a representation of the data in objects.
• Relational model 702 may correspond to database data structure 115
• object model 704 may correspond to object model 116.
• Mapping tool 701 interacts with VM 705, which may correspond to VM 124.
• System 700 is connected to a database 707 or storing data in relational form, and database 707 may correspond to database 118.
• a user operating with user interface 600 interacts with mapping tool 701 in order to enter and define the index groups.
• Mapping engine 703 converts data between relational model 702 and object model 704, and may perform the mapping using the exemplary mapping tool described above. In performing the conversions, mapping engine 703 uses index groups defined through user interface 600 in order to map the index groups between the relational and obj ect models.
• the user-entered definitions of index groups may be saved, such as in memory 104 or secondary storage 106, and the system may associated the saved index groups with the corresponding classes according to known methods.
• FIG. 8 is a block diagram of software modules including a runtime illustrating the operation of applications on data within a database. These modules may operate within the hardware elements shown in Figure 1.
• System 800 includes one or more applications 801 performing transactions on data within database 707.
• Application 801 interacts with a Java runtime 802, which includes a runtime cache 803 storing one or more objects 804 and 805 and a transaction manager 806.
• Runtime 802 also interacts with VM 705.
• System 800 may also accesses data in database 707.
• Objects are generated in runtime cache 803 as required by application 801, which accesses and operates on data within the objects.
• Transaction manager 806 tracks values to determine conflicts, as described, for example, in copending application of Tony Chun Tung Ng, filed on even date herewith, and entitled "User Interface for the Specification of Lock Groups.” Dete ⁇ nming conflicts does not necessarily involve use of index groups.
• system 800 determines if an index group exists for the requested data and, if so, it uses the index group to access an index for locating and retrieving the data. Index Group Processing
• FIG. 9 is a flowchart of an exemplary process associated with user interface 600 shown in Figure 6. This processing may be implemented by the modules shown in Figure 7 operating within the hardware shown in Figure 1.
• a user selects index group button 613 in order to view the appropriate information on user interface 700 (state 901).
• the user selects a class and optionally selects an index group from section 601 (state 901).
• buttons 610-612 state 902 and then selects one of the buttons 610-612 (state 903). If the user selected new button 611, the user enters .an index group name in field 607 and selects one or more fields for the index group from section 606 (state 904). The user also selects whether the index group is unique or non-unique by selecting a button in section 609 (state 905). When the user selects update button 610 (state 906), the system determines if at least one field is selected in section
• the system typically provides an error message (state 908), which may include presenting a section with a message indicating that at least one field must be selected. Otherwise, the system enters and stores the index group definition and adds it to the class listing in section 601 (state 909).
• a user may also update and delete index groups. To update an index group, a user selects fields for the index group using section 606 (state 910). When the user selects the update button, the index group is updated in accordance with the field selection and the selection concerning whether the index group is unique or non-unique, if at least one field was selected (states 905-909). If the user selected delete button 612 in state 903, the system deletes the definition for the selected index group .and removes it from the class listing in section 601 (state 911).

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• 1998
  • 1998-12-21 AU AU18337/99A patent/AU1833799A/en not_active Abandoned
  • 1998-12-21 EP EP98963287A patent/EP1008068A1/de not_active Withdrawn
  • 1998-12-21 WO PCT/US1998/027241 patent/WO1999033000A1/en not_active Application Discontinuation

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