Antonio Albano, Luca Cardelli, Renzo Orsini, Galileo: a Strongly Typed, Interactive Conceptual Language. ACM TODS, 10, 2, pp. 230-260, 1985.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....and the persistent independence properties have been thrown away. This means, that persistence has been integrated into the programming language with a weak level of transparency. Proposed database programming languages include Pascal R [55] DBPL [43] ADAPLEX [57] TAXIS [47] and Galileo [3]. At the same time, the idea of having orthogonal persistent programming languages has been introduced [4] The idea was to add persistence to programming languages in a way that persistent data are seamlessly managed with respect to transient data. Persistence is integrated into the programming ....

A. Albano, G. Ghelli, and R. Orsini. Galileo: A strongly-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230-260, 1985.

....by a design methodology [16] which includes guidelines, techniques, methods, and tools to support the activities of the designer. This report addresses the problem of identifying and factorising classes in class hierarchies, which constitute the database schemas in object oriented data models [2, 14, 3, 12]. A solution to this problem can be used to support integration of different user views in the conceptual design phase of an object oriented design methodology [11] schema normalisation in the implementation design phase, or schema integration in general, e.g. in multidatabase systems. An ....

....framework for integration of class hierarchies is described, where classes are identified using the equivalence relation and factorised using a join operator w.r.t. the subclass order. 2 Class hierarchies In this section, we introduce class hierarchies, similar to class hierarchies in Galileo [2], Goblin [12] O 2 [14] and TM FM [3] First, we give a BNF grammar that generates class hierarchies as defined by the database designer. Subsequently, we define a number of constraints which have to be imposed on class hierarchies to make them well defined. Finally, we introduce 2 flattened ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Trans. on Database Systems, 10(2):230--260, 1985.

....it has to be structured by a design methodology [14] which includes guidelines, techniques, methods, and tools to support the activities of the designer. This report addresses the problem of integrating classes in class hierarchies, which are the database schemas in object oriented data models [1, 13, 3, 11]. A solution to this problem can be used to support integration of different user views in the conceptual design phase or schema optimisation in the implementation design phase of an object oriented design methodology [10] or schema integration in general, e.g. in multidatabase systems. An ....

....of the join of the weak subtype relation and the join of the weak subfunction relation. Finally, in Section 5, the results are recapitulated and directions for future research are given. 2 Class Hierarchies In this section, we introduce class hierarchies, similar to class hierarchies in Galileo [1], Goblin [11] O 2 [13] and TM FM [3] Informally, a class hierarchy is a set of classes. A class has a name, a set of superclasses, a set of attributes, and a set of methods. An attribute has a name and a type, which can be a basic, set, or record type, or refers to a class. Hence, classes can ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Trans. on Database Systems, 10(2):230--260, 1985.

....and a heuristic algorithm is given to restructure and merge schema. In the last section, a summary and directions for further research are given. 2 Database schemas In this section, we introduce a subset of the database schemas found in object oriented database languages such as Galileo [2], Goblin [14] O 2 [17] and TM FM [4] Furthermore, we formalise these database schemas in terms of underlying types, underlying constraints, and functional forms. 2 Informally, an object oriented database schema is a class hierarchy, i.e. a set of classes related by a subclass relation. A ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Trans. on Database Systems, 10(2):230--260, 1985.

....2.2 An example database schema To illustrate the discussion in this paper, we will give example triggers based on the database schema shown in Figure 1. Its syntax is purely illustrative, yet based on trends in objectoriented modelling and object oriented database programming languages such as [2, 21, 19, 4]. The UoD described by the schema in Figure 1 has four classes, viz. board, cell, wire and colour table. All four class definitions begin with a description of the attributes their objects have. Only the classes board and cell have methods associated with them directly. All classes have, by ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: a strongly typed, interactive conceptual language. In The ACM transactions on database systems, volume 10, 1985.

....selection. We would like to borrow from objectoriented languages the idea that the programmer can control the sharing of methods through an explicitly de ned hierarchy of classes and that objects are manipulated only through methods de ned in these classes, achieving data abstraction. 3 Galileo [ACO85] integrates inheritance and class hierarchies in a static type system by combining the subtype relation in [Car88] and abstract type declarations. Galileo, however, does not integrate polymorphism or type inference. JM88] suggests the possibility of using their type inference method to extend ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230-260, 1985.

....inheritance is also used for maintaining extent inclusion; by the above assertion we usually assume that the set of Employee objects is a subset of the set of Person objects. Several object oriented database systems and languages have been proposed by using these two forms of inheritance [BDK92, ACO85] While IS A relation provides a compact and intuitively appearing way of organizing objects and methods, there seems to be no a priori reason why these two mechanisms should be controlled by simple partial orderings. For code sharing, IS A relation achieves some exibility of method application ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Transactions on Database Systems, Vol. 10, No. 2, pp. 230-260, 1985.

....recent. Examples of typed object oriented languages are Emerald, Trellis Owl [Schaffert 86] and Eiffel [Meyer 88b] All of them combine static type checking and dynamic binding. Explicit separate definition of types and implementations is present in Emerald and in the conceptual language Galileo [Albano 85] in the form of abstract and concrete types) #Persistent objects. Persistence is usually provided in languages for databases (FAD, Galileo) and distributed systems (Emerald) Other languages (Trellis Owl, Eiffel) provide persistent objects as an add on feature. In Guide, objects are ....

Albano A., Cardelli L., Orsini R., Galileo: a strongly typed, interactive conceptual language, ACM Trans. on Database Systems, vol. 10, 2 (june 1985)

....paradigm. See [6] for a survey in this eld. The necessary techniques to realize orthogonal persistence in a typed programming language have been established during the research and experimentation of persistent programming languages, most notably PS algol [5] The approaches so far proposed [4, 3, 19, 8, 2, 23, 10] are however restricted to a single language system persistent data must be created and Appeared in 25th Hawaii International Conference on System Science, 1992. accessed through a single prede ned programming language. This restriction is unacceptable when we want to use a persistent ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230-260, 1985.

.... database systems, either alone or embedded in a programming language, for object management (e.g. 34, 45, 43, 23] while the programming language based work attempted to use file systems or low level storage management systems to provide persistence of programming language structures (e.g. [6, 2, 61, 15]) Database systems support persistence and coarse grained concurrency control and consistency management, but they fail to satisfy the other functionality requirements and except for provision of meta data, they do not address the cross cutting issues. In addition, even in those areas of ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A Strongly-Typed, Interactive Conceptual Language. ACM Transactions on Database Systems, 10(2):230--260, 1985.

....entities with multiple and independent roles. The object behavior depends 23 strictly on the type through which the object is observed and there is no late binding. The difference from DOOR is the impossibility in Clovers of explicitly referring to the types in which one is interested. Galileo [2] allows objects to be dynamically extended with new types but the role mechanism is not provided. Thus objects always exhibit a uniform behavior no matter what type they are accessed through. Sciore s approach and Schrefl Neuhold s approach Taking a dramatically different approach of ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual 26 language. ACM TODS, 10(2):230--61, 1985.

....enough to support languages with similar type systems. 2 1 Introduction In recent years a range of single programming language systems have been developed that are supported by a persistent store[atk82,atk83b,ros83,bro85,that86,bro89] Examples of such systems include Argus[lis84] Galileo[alb85a], PS algol[psa88] and Smalltalk[gol83] Although each of these systems is based on a subtly different concept of persistence a common approach is to utilise a layered architecture. This paper presents the design of one such layered architecture that can be used to support a persistent object store ....

Albano A., Cardelli L. & Orsini R. Galilieo: A Strongly Typed, Interactive Conceptual Language. ACM Transactions on Database Systems, vol. 10, no. 2, 1985, pp230-260.

....Salary 100000 This function is polymorphic in the sense that it should be applicable to any relation S with Name and Salary fields of the appropriate type. In database programming languages there have been two general strategies. One is to follow the approach of Pascal R [Sch77] and Galileo [ACO85] and insist that the parameters of procedures are given specific types, e.g. function Wealthy(S:EmployeeRel) Delta Delta Delta. Type checking in both these languages is static and the database types are relatively simple and elegant extensions to the existing type systems of the programming ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, 1985.

....the extension of the relational model to build complex objects. Early extensions relaxed the first normal form requirement of the relational model, allowing set valued attributes ( Jae82] Dad86] The relational model has also been extended with abstract data types ( Row87] Mai87] Ban87a] [Alb85]) allowing the modelling of more complex types, where components or attributes of objects can be other database objects. We extend the relational data model similarly, and also succeed in applying relational types of algebraic operations to the model. Our algebra provides selection operations, ....

....response to queries. Osborn notes [Osb88] that the creation of new objects means that responses to a query cannot be identical. We propose new definitions for query equivalence that consider data as well as identifier equality (see Section 7) Many object oriented database systems (e.g. Mai87] [Alb85], Ban88] only support selection of objects already existing in the database. We recognize that many relationships requested by queries will exist in the database objects, but also feel that existing objects in the database may not necessarily reflect all relationships requested by a query. Thus, ....

Antonio Albano, Luca Cardelli, and Renzo Orsini. Galileo: A Strongly-Typed, Interactive Conceptual Language. Communications of the ACM, 10(2):230--260, June 1985.

....with the persistent store, this approach results in a name based persistence mechanism where any object (including those in its transitive closure) bound to a name in a binding space reachable from a specially designated root binding space automatically persists. The approach is based on Galileo [ACO85] and Napier [MBC 93] where environments correspond to binding spaces. The name management mechanism in PolySPIN is more general, however, since it supports objects defined in multiple languages. To participate in this mechanism, an object s class definition must inherit from a common base ....

Antonio Albano, Luca Cardelli, and Renzo Orsini. Galileo: A strong-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, June 1985.

....creation and modification of such database features as views, database procedures, integrity constraints and active rules. Moreover, they are weakly tolerant to other programming interfaces (perhaps, untyped) that may act on the same database. Persistent polymorphic PLs (Napier [MBCD89] Galileo [ACO85], Machiavelli [OBB89] Fibonacci [AGO95] Tycoon [Matt95] and others) retain the classical one threaded program control: they provide iterators for bulk types which conceptually assume the one data at a time processing. Some of them are also equipped with query capabilities, but rather as add ons ....

A. Albano, L. Cardelli, R. Orsini. Galileo: A Strongly-Typed, Interactive Conceptual Language. ACM Transactions on Database Systems, Vol.10, No 2, pp.230-260, 1985.

....public attributes of remote objects can be accessed in the same way as for local objects. However, the language also provides constructs to force the creation or execution of an object to take place at a specified node. Persistence is usually provided in languages for databases (FAD [4] Galileo [2]) and distributed systems (Emerald [6] Other languages (Trellis Owl [25] Eiffel [20] provide persistent objects as an add on feature. Objects in Guide are potentially persistent. However, only objects which are reachable from a persistent root are made persistent by the run time system; other ....

A. Albano, L. Cardelli and R. Orsini, Galileo: A Strongly Typed, Interactive Conceptual Language, ACM Trans.action on Database Systems, Vol. 10, No. 2 (1985).

....ObjectT) We allow multiple inheritance, that is, types may have more than one supertype. We assume that naming conflicts have already been resolved (for instance, by prefixing function names with type names) Classes. We strictly distinguish types from classes in the following sense (see also [ACO85, Bee89] Types are interface specifications (a collection of functions) whereas classes are containers for objects of some type (type extents) A class C is a collection object (an instance of the metatype class) For each 1 In this paper, we write a . T at the end of an identifier to make ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, June 1985.

....underlying it. 2. THE FRAMEWORK OF CONCEPTUAL MODELING LANGUAGES As the specific context of our research we will use a programming language that allows the definition of ISs at the conceptual level [4] This language is an adaptation of the language Taxis [22] with some influences from Galileo [1] and ADAPLEX [26] We present here only those aspects needed to provide a context for exception handling, and we refrain from using esoteric features in order to make the results of our investigations more widely applicable. We view an IS as a model of the world about which it contains ....

Albano, A., L.Cardelli and R.Orsini. Galileo: a strongly typed, interactive conceptual language. Technical Report TR 83-11271-2 (Murray Hill, NJ), Bell Laboratories, July, 1983. (To appear in ACM TODS).

....We allow multiple inheritance, that is, types may have more than one supertype. We assume that naming conflicts have already been resolved (for instance, by prefixing function names with type names) Classes and Views are strictly distinguished from types in the following sense (see also [ACO85, Bee89] Types are interface specifications (a collection of functions) whereas classes are containers for objects of some type (type extents) Each class or view, C, represents a (typed) set of objects and associates a type, the member type(C) to all objects in the set extent(C) The extent ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, June 1985.

.... conflicts have already been resolved (for instance, by prefixing function names with type names) Classes are strictly distinguished from types in the sense that types are interface specifications (a collection of functions) whereas classes are containers for objects of some type, see also [ACO85, Bee89] So, each class, C, represents a (typed) set of objects and associates the member type, mtype(C) to the objects in the set extent(C) The extent of a class is manipulated (so as to include or exclude member objects) either explicitly by corresponding operations or implicitly by ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly-typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, June 1985.

....4. The database Figure 2 shows a schema of the data base proposed here as the core of a virtual museum. The schema is subdivided into functional blocks, corresponding to the three levels in the structure of the data. The schema has been designed for the object oriented database language Galileo [ALB 85] and uses the following notation: Figure 1. Interacting entities and system structure 5 rectangles stand for classes of objects, while diamonds stand for associations among them, like in the classical entity relationship model. Subset of classes, or subclasses, are set of objects defined by ....

Antonio Albano, Luca Cardelli, Renzo Orsini, Galileo: a Strongly Typed, Interactive Conceptual Language. ACM TODS, 10, 2, pp. 230-260, 1985.

No context found.

A.Albano, L.Cardelli, R.Orsini: Galileo: a strongly typed, interactive conceptual language, Transactions on Database Systems, June 1985, 10(2), pp. 230-260.

....which is always accessed through its most specific role behaves exactly like an object in a traditional object oriented language. The languages proposed to deal with extensible objects may be classified as follows [ABGO93] ffl languages with dynamic binding and uniform behavior (e.g. Galileo [ACO85], AGO91] ffl languages with static binding and context dependent behavior (e.g. Clovers [SZ89] Views [SS89] IRIS [Fis87] and Aspects [RS91] ffl languages with both dynamic binding and context dependent behavior (e.g. Fibonacci [ABGO93] In this paper we discuss some possible ....

....the possibility of extending objects, but without introducing the notion of a context dependent behavior. We then show the linguistic and implementative effect of this first extension. This section is based on the linguistic and implementative model which underlies the first version of Galileo [ACO85]. msg 1 msg n method 1 method 1 fld 1 fld m offset 1 offset m Extended Object Type Descriptor (shared) method and field lookup table for owned and inherited properties ObjTypDescr field 1 field m . object Notation (used in all figures) object entry point: shared descriptor: Figure 1: The ....

A. Albano, L. Cardelli, and R. Orsini. Galileo: A strongly typed, interactive conceptual language. ACM Transactions on Database Systems, 10(2):230--260, 1985.

No context found.

A. Albano, L. Cardelli and R. Orsini, Galileo: a Strongly Typed, Interactive Conceptual Language. ACM Transactions on Database Systems 10 (2), 230-260 (1985).

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