W. Kim, N. Ballou, J. F. Garza, and D. Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Oce Information Systems, 9(1):31-51, January 1991.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....of the object oriented approach it is also important to take object oriented databases into consideration. There are not many distributed object oriented databases available at the moment. One system in the ITASCA database, which is the successor of the ORION database as described by Kim et al. [7]. It is not clear at the moment whether this system satisfies our requirements. Since the implementation will be designed for use with different applications, we will be able to test it with real applications soon. Two of them are presented in the following section, which describes some of the ....

Won Kim, Nat Ballou, Jorge F. Garza, and Darrell Woelk. A distributed object-oriented database system supporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, 1991.

....and the network link is broken, we would encounter the concurrency problems associated with having multiple copies of a file. The obvious approach to concurrency control in this context would be the checkout model found in most version control tools and some modern database systems (e.g. [18, 11]) In this model, each prefetched file would be locked in either a read only or writable mode, depending on whether the file is only needed for reading or possibly may be updated during the disconnected process fragment. These locks would be maintained persistently until later reconnection and ....

Won Kim, Nat Ballou, Jorge F. Garz, and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....has not been realized in Oz yet, as evidenced by the first two unused fields in the SUB ENV class. 5.2.4. 2 Object, Client, and Rule Ids Distributed object naming schemes have been thoroughly investigated in the distributed object oriented database community (see, for example, Orion 2 [65]) This is in general outside the scope of this thesis as a research topic, and we only present here a simple solution. The main goal in the design of the object id management is to reconcile the conflict between allowing autonomy in id assignment and still providing uniqueness. The solution here ....

Won Kim, Nat Ballou, Jorge F. Garza, and Darrel Woelk. A distributed objectoriented database system suporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....other facilities of MARVEL that are outside the scope of this paper) We intentionally prohibit automatic deletion of file attributes for safety reasons, since the bulk of the product data resides in file attributes. Schema restructuring is an open problem for object oriented database research [28, 21]. The Evolver works in the context of an existing MARVEL objectbase, with an existing data and process model. It accepts a new data model as input, and compares it to the existing class hierarchy; any renaming of classes or attributes is indicated on the command line. The tool presents to the ....

Won Kim, Nat Ballou, Jorge F. Garz and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems 9(1):31-51, January, 1991.

....late 80 s when several OODBs became commercially available. Earlier work on OODBs has mainly concentrated on centralized database environments, and only more recently has OODBs technology been applied in distributed systems environments (e.g. client server and and federated multiple databases [9, 5]) Most of distributed object management work is concentrated in two main areas: object oriented support for heterogeneous database systems, and distributed object storage management. But not much work has been done on enabling homogeneous distributed object oriented database system. A few ....

.... Object Database Sub Schema Composite object Classes corresponding to instance variables of a composite object composition link legend: Figure 4: Path Partitioning for Composite Object Automobile Drive Train Example 2 Let us consider the example schema illustrated in Figure 4 taken from [5].The class Automobile has a composite object drivetrain. This composite object is defined by instance variables Engine, transmission, Capacity, Size, Cylinders, type. The domain classes of the instance variables forming the composite object drive train are fAutomobile, A dt, A Eng, A trg. ....

W. Kim, N. Ballou, J.F. Garza, and D. Woelk. A distributed object-oriented database system supporting shared and private databases. ACM Trans. on Information Systems, 9(1):31-- 51, 1991.

....dependencies in turn transform into obligations, which have to be respected by each team member; however, the dependencies are negotiated and agreed bilaterally and therefore do not constrain the autonomy of team members. Distributed object oriented database systems developed so far, e.g. in [12]) do not fully support the requirements imposed by a cooperative engineering environment. In engineering and CAD CAM distributed object oriented database design, several earlier works suggest a cooperation architecture with one shared (public) database and several private databases [8, 11, 13, ....

W. Kim, N. Ballou, J.F. Garza, and D. Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transaction on Information Systems, 9(1):31--51, January 1991. 20

....paradigm. Such configurations are normally referred to as multidatabase or federated database systems. Current advances in multidatabases show the applicability of object oriented data models for the purpose of integrating diverse component data sources and supporting interoperability [19, 20]. The technical approach to object oriented multidatabase interoperability is based on an amalgamation of object oriented database concepts and distributed data management methodologies. 3 Middleware Facilities Most successful architectural approaches to distributed computing use middleware ....

W. Kim, N. Ballou, J.F. Garza, D. Woelk, "A Distributed Object-Oriented Database System Supporting Shared and Private Databases", ACM Trans. on Information Systems, vol.9, no. 1, Jan. 1991.

....has two time stamps : the time that the object was changed latest (CN) and the time when changes were last acknowledged (CA) An object is implementation consistent if its CN is before its CA. A composition is reference consistent if its CA is later than all the CN of its components. ORION 2 [Ki 91] also supports a message based notification approach where the system sends messages to notify users of potentially affected objects. The users can be notified immediately or at some later time specified by the user. The Version Server in [CGK89] resolves dynamic binding by specifying ....

Kim, W., Ballou, N., Garza, J.F., Woelk, D., `A Distributed ObjectOriented Database System Supporting Shared and Private Databases', in ACM Transactions on Information Systems, Vol 9(1), pp 31-51, jan 1991.

....Both Franklin [31] and Wang [198] discuss cache management algorithms that could have application in a dsm system. Object oriented database (oodb) systems are also interesting, as many of them have sophisticated page and object buffer cache management. oodb systems such as O 2 [17, 54] Orion 2 [120], and ObjectStore [125] also bear similarities to dsm systems. Their cache management systems are all similar in function to consistency management systems in dsm systems, but, as mentioned above, all rely on transactional support in the database system and are therefore difficult to apply ....

Won Kim, Nat Ballou, Jorge F. Garza, and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....as objects. In OMS, it is the responsibility of the distribution manager (see section 2.2.5) to know which hosts store which OMS partitions and databases. If a partition is moved (probably through some external action) then only the affected OMS distribution managers need to be informed. Orion 2 [45] and O 2 use a similar forwarding mechanism to allow objects to be migrated. Orion 2 requires that the cradle database remember the current database of the specified object. O 2 stores a reference to the current physical location of the migrated object at the disk location specified by the ....

Won Kim, Nat Ballou, Jorge F.Garza, and Darrell Woelk. A distributed object-oriented database system supporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....Container ID, WiSS Record ID) By a special mechanism it is achieved that object IDs are unique and never reused so that the object identity [KC86] required for object oriented databases can be guaranteed. The IDs always refer to the container partition where an object is created [WDH 82, KBGW91] If an object is moved to another container or partition, it retains its ID. In the original place, a forward marker is stored. Another approach would have been to use surrogates, but we rejected this because it incurs an additional indirection. 3.2 Process Architecture The process model of the ....

....protocol is run to adjust the virtual partitioning and to update out of date copies. 3. 5 Event Trigger Mechanism The event trigger mechanism makes it possible to automatically react to certain events in the system (active database [KDM88, BM91] The OMS is one of the few OODBMSs (see e.g. KBGW91, Pat90] offering such a mechanism in a distributed environment. A tool wanting to watch an event defines a callback function (Figure 8) and announces this at the local EM (LEM) i.e. setting an event) If this event cannot be processed by the LEM (e.g. an event on an object administrated on ....

Won Kim, Nat Ballou, Jorge F. Garza, and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....which is selected on. The result of a query is a set of unique object identifiers and the attribute values that were selected. A query may have more than one root if the different graphs of the roots overlap, i.e. if there is an attribute in common between all roots. 2.7. 2 Orion 2 Orion 2 [KBFW91] is a distributed version of Orion 1SX. It has a federated architecture and consists of a single shared database and a number of private databases. The Orion 2 architecture was adopted because it enhances the locality of objects to applications which most commonly use them. The configuration of ....

Won Kim, Nat Ballou, Jorge F.Garza, and Darrell Woelk. A Distributed ObjectOriented Database System Supporting Shared and Private Databases. TOIS, 9(1):31--51, January 1991.

....configurations are normally referred to as multidatabase or federated database systems. Current advances in multidatabase database technology have shown the applicability of object oriented data models for the purpose of integrating diverse component data sources and supporting interoperability [6, 7]. In fact, the technical approach to object oriented multidatabase interoperability is based on an amalgamation of object oriented database concepts and distributed data management methodologies. 3 Middleware Facilities for Distributed Computing Most successful architectural approaches to ....

W. Kim, N. Ballou, J.F. Garza, D. Woelk, "A Distributed Object-Oriented Database System Supporting Shared and Private Databases", ACM Trans. on Information Systems, vol.9, no. 1, Jan. 1991.

....is complete and the network link is broken, we encounter the concurrency problems associated with having multiple copies of a file. The obvious approach to concurrency control in this context would be the checkout model found in most version control tools and some modern database systems (e.g. [14, 11]) In this model, each pre fetched file would be locked in either a read only or writable mode, depending on whether the file is only needed for reading or possibly may be updated during the disconnected process fragment. These locks would be maintained persistently until later reconnection and ....

Won Kim, Nat Ballou, Jorge F. Garz, and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....has been reserved by a user, it may become available outside concurrency control mechanism. The owner of the reservation can decide to let other users access and even modify that object (e.g. through permissions granted on the private work area via the file system) Itasca (previously ORION 2 [Kim et al. 91] solves the second problem, through a distributed database incorporating private databases, into which objects are checked out from the shared database, as well as a query facility that distinguishes between private and shared databases. There is no access to objects outside of system control. ....

Won Kim, Nat Ballou, Jorge F. Garz and Darrell Woelk. A Distributed ObjectOriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems 9(1):31-51, January, 1991.

....databases. Specifically, it assumes an object oriented data model in the flavor of Marvel 3.1. As for the actual schema, some but not all of the schema must be identical. That is, a shared sub schema is required for process interoperability. On the other hand, no single schema system (like Orion 2 [30]) is assumed, and schemas of different sub environments can be arbitrarily different from each other. The details are discussed in 3.2.1. 3.1.4 Multiple Processes This is a key characteristic in the design of the architecture. I assume essentially different processes operating on the schemas, ....

....each SubEnv to be able to name objects, rules, and new SubEnvs autonomously, yet still guarantee uniqueness. This is the subject of this section. Object Ids Distributed object naming schemes have been thoroughly investigated over the years, especially in the area of distributed databases (e.g. [30]) This is in general outside the scope of this thesis. However, an approach which fits the requirements of a DEPCE is presented below. A short survey about object naming schemes will be given in the thesis. # Connection between a client, CL, and a remote server RS if RS is local then ....

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Won Kim, Nat Ballou, Jorge F. Garza, and Darrel Woelk. A distributed object-oriented database system suporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

....form of daemons which may be triggered. ORION resolves dynamic links on the basis of a time stamp ordering on the creation of versions while the Version Server resolves dynamic binding by specifying environments. ORION supports a flag based parallel editing notification mechanism [3] ORION 2 [14] also supports a message based notification approach where the system sends messages to notify users of potentially affected objects. The users can be notified immediately or at some later time specified by the user. With respect to composite objects [4] observe that it is sometimes desirable to ....

W. Kim, N. Ballou, J. F. Garza, and D. Woelk. A distributed object-oriented database system supporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, jan 1991.

....a context, the transactional mechanism must be modified and or extended to meet this new requirement. 3. 1 The check in check out model A lot of work has been done in the field of SEE s to furnish a framework which supports coordination by building mechanisms to manage long transactions [2] 9] [18] [21] 23] Generally, such work results in models for long transactions similar to the check in check out model [13] 16] 17] In this model, shared objects are taken from the central database and made available to users in their respective workspaces. Generally a workspace is implemented in the ....

W. Kim, N. Ballou J.F. Garza, and D. Woelk. A distributed object-oriented database system supporting shared and private databases. ACM TOIS, 9(1):31--51, January 1991.

....forward chaining path if the disk is too small and considering multiple paths if there is more free space. 4 Concurrency Control The obvious approach to concurrency control in this context would be the checkout model found in most version control tools and some modern database systems (e.g. [12, 13]) Each pre fetched file would be locked in shared or exclusive mode, depending on whether it is only to be read or possibly may be updated during the disconnected process fragment. These locks would be maintained persistently until later reconnection and checkin . But a more flexible approach is ....

Won Kim, Nat Ballou, Jorge F. Garz, and Darrell Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

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W. Kim, N. Ballou, J. F. Garza, and D. Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Oce Information Systems, 9(1):31-51, January 1991.

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Wom Kim, Nat Ballou, Jorge F. Garza, and Darrel Woelk. A Distributed Object-Oriented Database System Supporting Shared and Private Databases. ACM Transactions on Oce Information Systems, 9(1):31-51, January 1991.

No context found.

Won Kim, Nat Ballou, Jorge F. Garza, and Darrell Woelk. A distributed object -oriented database system supporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, 1991.

No context found.

W. Kim, N. Ballou, J. F. Garza, and D. Woelk. A distributed object-oriented database system supporting shared and private databases. ACM Transactions on Information Systems, 9(1):31--51, January 1991.

No context found.

Kim, W. , Ballou, N., Garza, F., Woelk, D.(1991). A distributed object-oriented database system supporting shared and private databases. TOI, 9(1). January 1991.

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Won Kim, N. Ballou, J.F. Garza, and D.; Woelk, "A Distributed ObjectOriented Database System Supporting Shared and Private Databases", ACM Trans. Inf. Syst., 9(1):31--51, January 1991.

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