D. Beech. A foundation for evolution from relational to object databases. In Proc. of the Int. Conf. on Extending Database Technology, 1988.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....viability. Any OODB which desires to make an impact in the marketplace is likely to find that customers vote with their dollars for SQL. Moreover, SQL is a reasonable candidate for the new functions suggested in this paper, and prototype syntax for several of the capabilities has been explored in [BEEC88, ANSI89]. Of course, additional query languages may be appropriate for specific applications or HLLs. Our last proposition concerns the architecture which should be followed when the application program is on one machine interfaced to a DBMS on a second server machine. Since DBMS commands will be coded ....

Beech, D., "A Foundation for Evolution from Relational to Object Databases," Proc. Conference on Extending Database Technology, Venice, Italy, April 1988.

....loop evaluation which may be very inefficient. Hence, the second phase unnests nested algebraic expressions to allow for more efficient evaluation. 1 Introduction Many declarative query languages for object oriented database management systems have been proposed in the last few years (e.g. [3, 5, 2, 18, 14]) To express complex conditions, access nested structure, or produce nested results, an essential feature found in these languages is the nesting of queries, i.e. the embedding of a query into another query. The optimization of object oriented (oo) queries has been intensively studied using ....

D. Beech. A foundation for evolution from relational to object databases. In EDBT, 1988.

....set, bag, list Table 2.1: Comparison of Object oriented Data Models. erational part of the reference data model. The next chapter identifies the requirements of such an object oriented query language. Chapter 3 Query Language Requirements Many object oriented query languages [Ser87, CDV88, Bee88, DLR88, CDLR89, BM89, BCD90, Kim90, BTA90, Ont91c, DGJ92, KKS92] have been implemented and proposed. Some of these query languages are designed particularly for object oriented databases, e.g. LIFOO [BM89] and ORION [Kim90] Many are, however, adapted from other areas: the relational data model ....

....implemented and proposed. Some of these query languages are designed particularly for object oriented databases, e.g. LIFOO [BM89] and ORION [Kim90] Many are, however, adapted from other areas: the relational data model and its extensions, e.g. ONTOS SQL [Ont91c] semantic data models, e.g. OSQL [Bee88] and object oriented programming languages, e.g. OPAL [Ser87] All of them, however, could be improved in one way or another. This chapter establishes a set of functional requirements for object oriented query languages which can be used to evaluate, compare, and improve existing query languages ....

[Article contains additional citation context not shown here]

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Proceedings of the International Conference on Extending Database Technology, volume 303 of Lecture Notes in Computer Science, pages 251--270. Springer-Verlag, 1988.

....allowed, storing query results is not addressed, and it is unclear if normal (value based) joins can be used. Other OODBMS companies are embarked on similar paths [7, 8] When object ids are added to the picture, the semantics of the corresponding language become more difficult to define. OSQL [5], developed as part of the Iris project [9] takes a functional view of objects and object ids. An object id is not simply a handle to an object, but an intrinsic property of the object that never changes. Attributes are modeled as functions applied to object ids. True functions, in the ....

D. Beech, "A Foundation for Evolution from Relational to Object Databases", Proc. of Int'l Conf. on Extending Database Technology, March 1988.

....= 1988] W orksin) Employees) Q COOL 2 = select[ 6= select[name = Smith livingin = Zurich ] Members) P rojects) The RELOOP language of the O 2 project is an SQL extension for the O 2 object model. It uses nested select from where blocks (the queries shown here look the same in OSQL of IRIS [14]) Q RELOOP 1 = select e from e in Employees where exists ( select p from p in Worksin(e) where pname(p) OODB and start(p) 1988 ) Q RELOOP 2 = select p from p in Projects where exists ( select e from e in Members(p) where name(e) Smith and livingin(e) Zurich ) The language ....

....in selection predicates or the way restructuring is expressed, have been attacked differently in complex object languages. Currently, the same is true for the object languages that have been proposed. This evolutionary aspect of query language design for object models is particularly stressed in [14, 16, 33, 53, 26, 120, 99]) 5 Conclusion We gave an overview of research directions that have been, and continue to be, pursued in the field of extended relational databases. We have classified extensions to the relational model according to a programming language oriented view of data models. In this view, a data model ....

D. Beech. A foundation for evolution from relational to object databases. In J.W. Schmidt, S. Ceri, and M. Missikoff, editors, Advances in Database Technology --- EDBT'88. LNCS 303, Springer Verlag, Heidelberg, March 1988.

.... the other hand SQL has been successfully adapted to semantic data models [HK87, EGH 92, HE92] and there have been many proposals for applying SQL to OODB [BCD89, CDLR90, DGJ92, GV92, KKS92, BH93] A number of these SQL variants have already found their way into commercial products like OSQL [Bee88] in IRIS, Object SQL [HD91] in ONTOS, RELOOP [CDLR90] and its successor O 2 Query [BDK92] in O 2 , CQL [DGJ92] in Ode, XSQL [KKS92] in ORION. A derived form of O 2 Query is being considered as the query language OQL of the ODMG 93 standards proposal [Cat94, Kim94] Unfortunately the syntax of ....

D. Beech, A Foundation for Evolution from Relational to Object Databases, Advances in Database Technology, Proc. Int. Conf. on Extending Database Technology (EDBT) (J.W. Schmidt, S. Ceri, and M. Missikoff, eds.), Springer, Berlin, LNCS 303, 1988, pp. 256--270.

....of this trend. Important work on dynamic aspects of databases includes practically oriented research on behavior modeling and transaction design [9 11,24,27,28] encapsulating both structural and behavior data, e.g. object oriented databases including Gemstone [15] Vbase [6] O 2 [25,26] IRIS [7], etc. and also includes theoretical studies on transactions as specification languages [2,4] and on dynamic integrity constraints [13,16,32,33] Previous studies on modeling database behavior can be roughly categorized into two approaches. One uses behavioral constructs to describe semantic ....

D. Beech, A foundation for evolution from relational to object databases, in: J. W. Schmidt, S. Ceri and M. Missikoff, eds., Advances in Database Technology --- EDBT'88, Lecture Notes in Computer Science, Vol. 303 (Springer, Berlin, 1988) 251--270.

....SQL is the standard language for database access. Like democracy, it may not be perfect, but it s better than anything else that s around. Ken Jacobs, cited in [Hazza90] It is socially irresponsible to invent new languages if an existing language is a good approximation to what is required. [Beech88] Some of the drawbacks of using an Object SQL (based upon DAPLEX) have been highlighted by [Gray92] Syntax of OSQL may be similar to SQL, but the semantics may be quite different (e.g. implicit joins, unexpected behaviour of familiar constructs) Limited computational power. Restrictive ....

Beech, D. A foundation for evolution from relational to object databases. Advances in Database Technology - EDBT '88. Lecture Notes in Computer Science, 303, pp. 251-270, Springer-Verlag, Berlin, 1988.

....can be stored in an OODB using the schema shown in figure 4. In this context, there is no need for an intermediate construct (corresponding to the component relation) as the relationship is represented by a direct reference from one related class to the other. Using a revised OSQL notation [4], the example rule can be expressed as: if crs.title = Computing and mod in component(crs) and mod.level = 4 from crs in course, mod in module do action In such a rule, the insertion of a course object plus its attributes would lead to a test on that object to see if it has a ....

D. Beech. A foundation for evolution from relational to object databases. In J.W. Schmidt, S. Ceri, and M. Missikoff, editors, Advances in Database Technology (EDBT), pages 251--270. Springer-Verlag, 1988.

....nested loop evaluation which may be very inefficient. Hence, the second phase unnests nested algebraic expressions to allow for more efficient evaluation. 1 Introduction Many declarative query languages for object oriented database management systems have been proposed in the last few years (e.g. [3, 5, 2, 15, 11]) To express complex conditions, access nested structure, or produce nested results, an essential feature found in these languages is the nesting of queries, i.e. the embedding of a query into another query. The optimization of object oriented (oo) queries has been intensively studied using ....

D. Beech. A foundation for evolution from relational to object databases. In Proc. of the Int. Conf. on Extending Database Technology, 1988.

....can be found in [KSK92] Appeared in ACM SIGMOD Conference on Management of Data, San Diego, CA, June 1992, pages 393 402 y Work supported in part by the NSF grants IRI 8903507 and CCR 9102159. On sabbatical leave from Stony Brook University. 1 Introduction In recent years, several papers [BANC90, BEEC88, CLUE89, DLR88, KS90, 1] have proposed query languages for object oriented databases. However, none of these languages captures (or even attempts to deal) with all the aspects of the object oriented model. In this paper, we present a new query language that incorporates features not found in earlier languages. The ....

....some of the salient features of a new language for querying object oriented databases. The language is capable of expressing sophisticated queries in a very concise way. This is achieved via extended path expressions, which are more expressive than any of the previous manifestations (for example, [ZAN83, BEEC88, CLUE89, DLR88]) of the dot notation for nested structures. We extended path expressions with the concept of selector, accommodated methods, and higher order variables that range over method names and classes. The use of higher order variables endows our language with truly novel capabilities that allow the ....

Beech, D., "A Foundation for the Evolution from Relational to Object Databases," Proc. EDBT Conf., Venice, Italy, 1988, pp. 251--270.

....the increased expressiveness of the model be used to guide the user in constructing meaningful queries without leading to proportionately more complex query interfaces Related work on query interfaces to OODBs reviewed in section 2. 1 indicates that systems have been put forward which are textual [Bee88, BCD89] form based [MZO90, Dea90] and graph based [Gea85, GPT93] However, there have been few empirical studies of the effectiveness of different interface paradigms, and it is difficult to argue conclusively that any one strategy is superior to others. Indeed, as discussed in section 2.2, it ....

....paradigms may be supported with comparable ease, and further that automatic conversion between them is possible. Most commercial database systems offer an SQL like query language. To support the addi3 tional constructs of OODBs, SQL can be extended with some object constructors and operators [Bee88, BCD89] and the emerging SQL 3 standard is likely to include a range of facilities for manipulating object oriented extensions to the relational model. Some OODBs are only accessible using programming languages. General advantages of form based and graph based interfaces over their textual ....

[Article contains additional citation context not shown here]

D. Beech. A foundation for evolution from relational to object databases. In J.W. Schmidt, S. Ceri, and M. Missikoff, editors, Advances in Database Technology (EDBT), pages 251--270. Springer-Verlag, 1988.

....Objects are displayed by ensuring that every class has a public method called print that displays the relevant information that the objects stands for. A method called identify is also used for an object to identify itself when it is displayed as an attribute of another object. 5. In [8] Beech discusses the migration from relational systems to OO systems concentrating on the query language. He presents a language called OSQL , based on a reinterpretation and an extension to SQL. This involves quite a simple OO model where classes are basically complex types (a record of ....

David Beech. A foundation for evolution from relational to object-oriented database. In Lecture Notes in Computer Science, volume 303. Springer-Verlag, 1988. Advances in Database Technology.

....or (Profitability(u) contains y and Greater(y,5) We do not describe the full language, but restrict ourselves to the fundamental concepts. We ignore issues such as object deletion and addition as well as inheritance (see for more information [55, 81] Unlike OSQL (object SQL, see [14]) functions, FQL functions can be recursive or even mutually recursive. Like Datalog, FQL has a fixpoint semantics that can be computed within finite time or more precisely within a time bounded by a polynomial function in the size of the database. There are three different types of PFQL ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology - EDBT'90, pages 60--74. Springer-Verlag, 1990.

....based on: ffl user set priorities for classes and attributes and or, ffl user provided guessed queries and or ffl the information closure of an object. In order to exemplify our ideas, we use the objectoriented language FQL [SW94] The syntax of FQL is similar to the syntax of OSQL [Bee88, WLH90]. Unlike the specifications of OSQL functions, the specifications of FQL functions can be recursive. There are three different types of FQL functions: stored functions, built in functions, and derived functions. Similarly to OSQL [Bee88] stored functions are stored by means of tables. A ....

....The syntax of FQL is similar to the syntax of OSQL [Bee88, WLH90] Unlike the specifications of OSQL functions, the specifications of FQL functions can be recursive. There are three different types of FQL functions: stored functions, built in functions, and derived functions. Similarly to OSQL [Bee88], stored functions are stored by means of tables. A built in function is defined procedurally. For instance, given some numbers, the built in function sum computes the sum of these numbers. Finally, derived functions are defined in a declarative way. To illustrate, suppose we have an ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology (EDBT'88), pages 251--270. Springer-Verlag, 1988.

....or (Profitability(u) contains y and Greater(y,5) We do not describe the full language, but restrict ourselves to the fundamental concepts. We ignore issues such as object deletion and addition as well as inheritance (see for more information [43, 62] Unlike OSQL (object SQL, see [9]) functions, FQL functions can be recursive or even mutually recursive. Like Datalog, FQL has a fixpoint semantics that can be computed within finite time or more precisely within a time bounded by a polynomial function in the size of the database. There are three different types of PFQL ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology - EDBT'90, pages 60--74. Springer-Verlag, 1990.

....on the object (tuple respectively) or the function (attribute respectively) level. This decision is taken by the underlying data model. Our concepts will be illustrated on the theoretically well founded ( 62] object oriented language FQL . This language is a modified version of OSQL ([8]) which evolved from the DUPLEX model ( 65] There are three different types of FQL functions: stored functions, built in functions, and derived functions. Stored functions are stored by means of tables. For instance, a table may store the parents of persons. A built in function is defined ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology (EDBT'88), pages 251--270. Springer-Verlag, 1988.

....expressions, and restructuring. Since no generalization hierarchies are supported, object preserving operations do not require classification. OSQL of Iris. Iris is an object oriented database system of Hewlett Packard Research Laboratories in Palo Alto. Its SQL like query language is called OSQL [45, 9]. OSQL has the philosophy of being a very natural extension of the standard SQL language. The Iris data model is an object function model providing set valued functions. OSQL allows (even nested) function applications (the equivalent of path expressions) OSQL does not provide any complex object ....

....of the standard SQL language. The Iris data model is an object function model providing set valued functions. OSQL allows (even nested) function applications (the equivalent of path expressions) OSQL does not provide any complex object features such as nesting of subqueries. As introduced in [9], the OSQL semantics is to deliver data, that is, no object preserving semantics are provided. RELOOP of O 2 . O 2 is an object oriented database system developed by Altair, Paris. The SQLbased query language is called RELOOP [13] O 2 is a complete object oriented database system in providing ....

D. Beech. A foundation for evolution from relational to object databases. In J.W.Schmidt, S.Ceri, and M.Missikoff, editors, Advances in Database Technology --- EDBT 1988, Springer LNCS 303, Heidelberg, March 1988.

....system query language PFQL which is able to handle application domains as described above. PFQL is a proper extension of the functional query language FQL which was shown to have outstanding expressive power ( 12] FQL in turn is an extension and slight modification of OSQL ([2, 13]) on recursively defined functions. We restrict ourselves here to that part of PFQL which provides the semantics of function definitions. Other aspects such as inheritance of functions, and creation and deletion of objects have been carefully discussed in the context of FQL ( 9] The study ....

....functions are indispensable for most applications. PFQL allows user defined functions, so called built in functions. Such built in functions can be Sum computing the sum of a bag of integers (e.g. Sum( 1; 1; 1; 2; 3] 8] Div computing the division between real numbers (e.g. Div( 8] 4] [2]) and Greater mapping two real numbers to true or false (e.g. Greater( 4] 3] true] The mentioned extended Datalog is also not able to compute the bill of material problem which can be expressed in FQL ( 12] and consequently also in PFQL . We illustrate the power and the need to ....

[Article contains additional citation context not shown here]

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology - EDBT'90, pages 60--74. Springer-Verlag, 1990.

....It also permits a user to modify the schema easily, or to build on an existing schema. Iris also allows both forms of relationship 3 We expect many scientific schemas to contain hundreds of classes. It is quite easy to forget what names have already been used for relationships. creation [Bee88] Each class create statement must specify the kind of the class. Each relationship create statement may specify the properties of the relationship in each direction. If left unspecified, the properites obtain default values of association, N 1, mutable, and with null objects permitted. The ....

....required setof to Plant; create immutable haspart input from Experiment to Weather; create immutable required haspart plants from Experiment to Plant community; Note that the relationship from Plant community to Plant uses the default label Plant. The keyword required, borrowed from Iris [Bee88] indicates that null values are not allowed. The next statement changes the label from Experiment to Plant community to be system (to match Figure 1) relabel plants from Experiment to Plant community with system; Inheritance is specified as part of the class create statement, before listing ....

D. Beech. A foundation for evolution from relational to object databases. In Proceedings of the International Conference on Extending Database Technology, pages 251--170, Venice, Italy, March 1988.

....or (Profitability(u) contains y and Greater(y,5) We do not describe the full language, but restrict ourselves to the fundamental concepts. We ignore issues such as object deletion and addition as well as inheritance (see for more information [23, 39] Unlike OSQL (object SQL, see [5]) functions, FQL functions can be recursive or even mutually recursive. Like Datalog, FQL has a fixpoint semantics that can be computed within finite 2 RULE LANGUAGES 32 time or more precisely within a time bounded by a polynomial function in the size of the database. There are three ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology - EDBT'90, pages 60--74. Springer-Verlag, 1990.

....variable e: set [sal : 30000] e) We call this partial assignment , because it has no effect on the salary of other employees. Operations for object evolution: besides being created and deleted, objects might also gain or lose types dynamically, similar to add remove type in the IRIS model [9], and to specialize in [16] For example, we create a new instance of type Pers by: create [P ers] p) Here, p has to be a variable of type Pers or a supertype. The object type is instantiated and the new object is assigned to the variable, which can then be used in partial assignments, for ....

D. Beech. A foundation for evolution from relational to object databases. In Advances in Database Technology --- EDBT'88. LNCS 303, Springer Verlag, Heidelberg, March 1988.

....respectively) or the function (attribute respectively) level. This decision is taken by the underlying data model. Our concepts will be illustrated on the theoretically well founded ( 19] and implemented ( 13, 17] object oriented language FQL . This language is a modified version of OSQL ([4]) which evolved from the DUPLEX model ( 20] There are three different types of FQL functions: stored functions, built in functions, and derived functions. Stored functions are stored by means of tables. For instance, a table may store the parents of persons. A built in function is defined ....

D. Beech. A Foundation for Evolution from Relational to Object Databases. In Advances in Database Technology (EDBT'88), pages 251--270. Springer-Verlag, 1988.

....relational query language. On the other hand SQL has been successfully adapted to semantic data models [32, 30] and there have been many proposals for applying SQL to OODB [8, 16, 19, 22, 34, 14] A number of these SQL variants have already found their way into commercial products like OSQL [11] in IRIS, Object SQL [26] in ONTOS, RELOOP [16] and its successor O 2 Query [9] in O 2 , CQL [19] in Ode, XSQL [34] in ORION. A derived form of O 2 Query is being considered as the query language OQL of the ODMG 93 standards proposal [15, 35] Unfortunately the syntax of many of these query ....

D. Beech, A Foundation for Evolution from Relational to Object Databases, Advances in Database Technology, Proc. Int. Conf. on Extending Database Technology (EDBT) (J.W. Schmidt, S. Ceri, and M. Missikoff, eds.), Springer, Berlin, LNCS 303, 1988, pp. 256--270.

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D. Beech. A foundation for evolution from relational to object databases. In Proc. of the Int. Conf. on Extending Database Technology, 1988.

No context found.

D. Beech. A foundation for evolution from relational to object databases. In Proc. of the Int. Conf. on Extending Database Technology, 1988.

No context found.

D. Beech, "A Foundation for Evolution from Relational to Object Databases," in Advances in Database Technology---EDBT '88, J. W. Schmidt, S. Ceri & M. Missikoff, eds., Springer-Verlag, New York--Heidelberg-- Berlin, 1988, 251--270.

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