P. Buneman, R. E. Frankel, and R. S. Nikhil. An implementation technique for database query languages. ACM TODS, 7(2), 1982.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....no simple syntactic characterization) that can be evaluated in pspace, and this set of schemas is sufficient to express all pspace queries. 1 Introduction A number of database languages with a functional flavor have been proposed, including, for instance, relational algebra [Cod70] and FQL [BFN82]. The algebra for complex values [AB88] which generalizes Codd s Algebra, is of the style [Bac78] based on a small set of operations that can be composed. An alternative approach based on variables and abstractions is used in [HKM93] Yet a third one with an object oriented flavor is considered ....

P. Buneman, R. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM Transactions on Database Systems 7(2):164--186, 1982.

....description and manipulation of object oriented databases . Functional programming , with its emphasis on abstraction and on data types, might provide more insight into object oriented database problems. There is a growing body of work on functional query languages, from the early FQL language of [11] to the more recent work on structural recursion as a query language [8, 10, 9, 25, 39] In this context, it is natural to ask: Is there a functional analog of the logical framework of first order and fixpoint formulas over finite structures In [21] we partly answered this question by computing ....

P. Buneman, R. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM Trans. on Database Systems, 7 (1982), pp. 164-- 186.

....the complexity wrt. navigations and the implementation of lazy mediators. Note that we use the terms lazy and demand driven synonymously, whereas in the context of functional languages, lazy evaluation refers to a specific and di#erent on demand implementation technique for non strict languages [2,9]. Our XML query language XMAS borrows from similar languages such as XML QL, MSL, FLORID, Lorel, and YAT [17,15,7,1,4] However, most of the above rely on Skolem functions for grouping, while XMAS uses explicit group by operators thereby facilitating a direct translation of the queries into an ....

P. Buneman, R. E. Frankel, and N. Rishiyur. An Implementation Technique for Database Query Languages. ACM TODS, 7(2):164--186, June 1982.

.... Thus on the one hand, we significantly extend the models presented in [Shi81, BF79] and on the other hand, we obtain powerful optimization facilities that are not possible in models such as [PK90, ACo85] Note that algebraic optimizations are not investigated in the work of [Shi81, BF79, BFN82] either. Traditionally, the process of optimization is divided into two consecutive steps: algebraic optimization and access path optimization, which is not performed algebraically. In this paper we shall show that the functional model allows the latter kind of optimization to be done ....

....amenable to parallel execution is well understood, but the interesting question is now how to integrate the above rules with the two other optimization strategies. Will access path optimization still be the first to try Additional potential for optimization lies in taking a lazy query evaluator [BFN82] thus leaving the strict semantics of FP programs: i) unnecessary evaluations and database accesses are avoided because of call by need parameter passing and (ii) pipelining is already included in the execution of such an interpreter; hence some rules become redundant in the optimization cycle, ....

[Article contains additional citation context not shown here]

BUNEMAN, P., FRANKEL, R.E. & NIKHIL, R.: An Implementation Technique for Database Query Languages, ACM Transactions on Database Systems Vol. 7, No. 2, 1982, pp. 164186.

....the complexity wrt. navigations and the implementation of lazy mediators. Note that we use the terms lazy and demand driven synonymously, whereas in the context of functional languages, lazy evaluation refers to a specific and different on demand implementation technique for non strict languages [2, 9]. Our XML query language XMAS borrows from similar languages such as XML QL, MSL, FLORID, Lorel, and YAT [17, 15, 7, 1, 4] However, most of the above rely on Skolem functions for grouping, while XMAS uses explicit group by operators thereby facilitating a direct translation of the queries into ....

....the query result. We assume this step has been done before starting the LXP. Example 6 (Liberal LXP) Let u be the URI of the complete tree t = a[b[d; e] c] A possible trace is: get root(u) 0 get a handle for the root fill ( 0 ) a[ 1 ] return a hole for a s children fill ( 1 ) b[ 2 ]; 3 ] nothing to the left of b; possibly more to the right fill ( 3 ) c] nothing left right below of c fill ( 2 ) 4 ; d[ 5 ] 6 ] there s one d and maybe more around fill ( 4 ) dead end fill ( 5 ) also nothing here fill ( 6 ) e] another leaf 2 The use of ....

P. Buneman, R. E. Frankel, and N. Rishiyur. An Implementation Technique for Database Query Languages. ACM TODS, 7(2):164--186, June 1982.

....vValOf db sub. 3.3 Lazy retrieval of surrogate value pairs Versioning allows for straightforward implementation of lazy retrieval in a state transition sequence. When a certain version is retrieved by allDB, the version is also locked so that lazy reading is performed safely. As described in Ref. [3], lazy retrieval of a locked version by allDB and vAllOf can be implemented using a currency pointer and find first followed by a series of the find next operation. A following update operation to the locked version will generate a new version with the specified modification (Figure 6) 3.4 ....

P. Buneman, R. E. Frankel, and R. Nikhil. An implementation technique for database query languages. ACM Trans. on Database Syst., 7(2):164--186, 1982.

....The last group of LDM operations include the operations: Cartesian product, union, difference and projection. These operations are again defined very similarly to the corresponding relational algebra operations. 2. 3 Functional database query languages The functional query language FQL [16, 17] and its successors the languages GDL [12] and O 2 FDL [53] had a strong influence on the design of the OVAL query language. The main characteristic of the FQL query language is its small set of simple functional operations which can be combined using the function composition operation. ....

....on a set of powerful functional operations intended for querying the database. It has been used as a programming language for a parallel database system. The following paragraphs provide an overview of the main features of FQL, GDL, O 2 FDL and FAD. 2.3. 1 FQL The Functional Query Language (FQL) [16, 17] is based on ideas concerning the functional programming language FP proposed by Backus [10] The database structure is represented by the functional database model. The object static properties are modelled by functions that map from instances of the given type to instances of the type ....

P. Buneman, R.E. Frankel, R. Nikhl, An Implementation Technique for Database Query Languages, ACM TODS, Vol.7, No.2, June 1992, pp. 164-186

....model for integrating heterogeneous schemas in multidatabase systems [28] In order to gain the full benefit of the functional paradigm in a database context, however, it is necessary to combine the FDM with a functional data language. The two earliest such languages were Daplex [98] and FQL [16]. Daplex is a high level, end user language which describes the evaluation and manipulation of sets of database values, while FQL takes a stream based view of computation and is intended to be used as an internal data language. Both languages are declarative, relatively concise and are amenable to ....

....of explicit state changes. Functional Query Languages Recognising the difficulties of handling updates in a functional way, and not wishing to compromise the clarity and conciseness of their languages in order to support some theoretical notion of state change, the developers of some systems [16, 6] have restricted the scope of their languages to handling database queries only. Embedded Update Commands in a Functional Language The final approach, and the one that has been most widely adopted, is to provide the user with a set of update functions which are allowed to side effect the ....

P. Buneman and R.E. Frankel. An Implementation Technique for Database Query Languages. ACM Transactions on Database Systems, 7(2):164--186, June 1982.

....attention has been given to algebras without Powerset for PTIME queries. An elegant way of manipulating complex object databases, related to our paper, is based on functional programming. There has been some practical work in database query languages in this area, e.g. the early FQL language of [8] and the more recent work on structural recursion as a query language [6, 7, 28] One important difference of the framework developed here from [6, 7, 28] is that we use the pure TLC without any added recursion operators (the equality predicate and atomic constants used in our presentation are ....

P. Buneman, R. E. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM Trans. on Database Systems, 7 (1982), pp. 164--186.

....viewed as a framework for database query languages which is between the declarative calculi and the procedural algebras. After all it is called a calculus, but reductions are procedural. Similar frameworks underlie some practical work in database query languages, e.g. the early FQL language of [11] and the more recent work on structural recursion as a query language [9, 10] An important difference from [9, 10] is that here we use the pure typed calculus and we use no type polymorphism. The second contribution of this thesis is a study of the expressive power of fixed order fragments of ....

....in this thesis leads to a number of interesting questions: 1. What is the expressive power of TLI = k and MLI = k for k 3 In particular, is the converse of Theorem 6.3.5 true as conjectured in Section 7.5 2. In our embeddings we use lists of tuples, which are inherently ordered. In [1, 11, 9] sets are used as basic constructs, and set iteration replaces list iteration in [11, 9] Is it possible to eliminate the order dependence in our framework by augmenting the calculus syntax and semantics with set iteration One approach might also be to encode finite structures using a generic ....

[Article contains additional citation context not shown here]

P. Buneman, R. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM Trans. on Database Systems, 7 (1982), pp. 164--186.

....practical interest. Functional programming, with its emphasis on abstraction and on data types, might provide more insight into oodb query languages; and is the paradigm of choice in many oodbs. Thus, there is a growing body of work on functional query languages, from the early FQL language of [10] to the more recent work on structural recursion as a query language for complex objects [7, 8, 9, 30, 47] In this context, it is natural to ask: Is there a functional analogue of the logical framework of first order and fixpoint formulas over finite structures In [25] we partly answered this ....

P. Buneman, R. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM Trans. on Database Systems, 7 (1982), pp. 164--186.

....(with no simple syntactic characterization) that can be evaluated in pspace, and this set of schemas is sufficient to express all pspace queries. 1 Introduction A number of database languages with a functional flavor have been proposed, including, for instance, relational algebra [Cod70] and FQL [BFN82]. The algebra for complex values [AB88] which generalizes Codd s Algebra, is of the style [Bac78] based on a small set of operations that can be composed. An alternative approach based on variables and abstractions is used in [HKM93] Yet a third one with an object oriented flavor is considered ....

P. Buneman, R. Frankel, and R. Nikhil. An implementation technique for database query languages. ACM Transactions on Database Systems 7(2):164--186, 1982.

....mechanism could be exploited to save work at run time, while leaving the program clean, clear and elegant. In our implementation, we concentrated on minimizing disk I O; we attempt to read a block of information only if at least part of that block is needed to answer a query. Buneman et al. [7] explored a similar approach in connection with relational database systems. ffl To deliver initial results promptly. It is a commonplace of user centered design that the most important speed measure of any system is how long it takes to deliver its first result to the user. If the user can be ....

Peter Buneman, Robert E. Frankel, and Rishiyur Nikhil. An implementation technique for database query languages. ACM Transactions on Database Systems, 7(2):164--186, 1982.

....are able to execute queries in parallel and distributed by means of interaction. Our schema of execution resembles graph reduction techniques [TBH82] The computation of terms is postponed until necessary, which is known as lazy evaluation. A similar approach to query processing was presented in [BFN82] The query system is conceptually an object society of its own. It is defined using the same concepts being used for any other object society. Therefore, it can be implemented using an existing environment and can thus be easily integrated into the environment. The interface to the society ....

....i.e. intermediate results are evaluated only when they are needed. The evaluation of terms is postponed until necessary (lazy evaluation) The technique is well known for functional languages and has been proposed for the processing of database queries using the functional query language FQL [BFN82] A reduction step consists of bringing into existence subordinate query objects to evaluate subqueries. Whenever an input operand is to be evaluated, the query object representing the current term has to wait until the input operand is available, i.e. until the subquery has been evaluated. As ....

Buneman, P.; Frankel, R.; Nikhil, R.: An Implementation Technique for Database Query Languages. ACM Transactions on Database Systems, Vol. 7, 1982, pp. 164--186.

....methods as the core new feature of OODBs. This is a functioncentric (or method centric) view of data as opposed to the structure centric view of data in relational databases (e.g. in [28, 41] Interesting functional approaches to database query languages have been advocated in the past, e.g. [15, 38], but much remains to be done in this area. Because of the function centric character of OODBs we believe that this is one of the most promising approaches to the problem of their formalization. Note that some of the actual query languages in OODB prototypes are functional [9] and that recent ....

....For example, the typed calculus with equality is the simplest syntax to date, that can be used to describe the complex object algebra of [1] In our embeddings we use lists of tuples and Functional Programming Formalisms for OODB Methods 27 simulate sets by eliminating duplicates. In [1, 15, 13] sets are used as basic constructs, and set iteration replaces list iteration in [15, 13] One open question is: how can the calculus syntax and semantics be augmented with set iteration Not all database query languages can be embedded in the typed calculus. Any computation that is not ....

[Article contains additional citation context not shown here]

P. Buneman, R. Frankel, and R. Nikhil. An Implementation Technique for Database Query Languages. ACM TODS, 7 (1982), pp. 164--186.

....(AB) ffi with the relation r, then we lose the information that two distinct objects, namely 1 and 2, map onto the same tuple a 1 b 1 . The attributes as functions approach as described here is inspired by [Spy 85] and it is similar to the approach taken in many functional data models [BuF 79] BFN 82] Shi 81] 3 Object Functional Dependencies, Consistency and Satisfaction For the remaining of this paper, we adopt the following notational conventions. First, for every set of attributes X, we write X ffi (o) to stand for X ffi is not defined on object o , and X ffi (o)6= to stand ....

Buneman P., Frankel R., Nikhil R., "An implementation Technique for Database Query Languages", ACM-TODS, vol 7, No2, June 1982.

.... Software Engineering (CASE) method it generates a product quality CASE tool supporting that method [1] The generated CASE tool operates on an underlying database (database) of a form developed by the Eclipse project [2, 3] whose design has been greatly influenced by the Functional Model of Data [4, 5]. ToolBuilder implements data transformations in four stages: 1. The relationship between the data models is specified by a transform between them. 2. Programs are generated, using the transform which will dump the data from any database having the host data model and load it into any database ....

Buneman P., Frankel R.E. and Nikhik R., An implementation technique for database query languages, ACM Transactions on Database Systems 7(2), June 1982.

....efficiency of comprehensions over bulk types other than lists have not yet been attempted, but the lambda calculus semantics of comprehensions makes proof or disproof possible. Pragmatic evidence for the efficiency of list processing is given by commercial products that use it, for example in FQL [8], and by the speed of a prototype parallel database machine which uses list comprehensions [21] 3.4 Integration Syntactic Integration It is important that the syntax of the query notation is consistent with the syntax of the remainder of the language. For some languages a keyword style may be ....

Buneman P. Nikhil R. Frankel R. An Implementation Technique for Database Query Languages. ACM Transactions on Database Systems 7,2 (June 1982), 164-187.

....and Pi 2 def = map(snd ) are relational projections (on sets of tuples. ffl ae 1 = map(hsnd ; fsti) ffi ae 2 ffi hsnd ; fsti. ae 1 is like ae 2 , but pairs to the left. ffl cartprod def = ffi map(ae 1 ) ffi ae 2 . ffl unnest 2 def = ffi map(ae 2 ) It is interesting to note that FQL [7], a language designed for the pragmatic purpose of communicating with functional network databases was based roughly on the same set of operators as MA. Translation from MC( Sigma) to MA( Sigma) An MC( Sigma) expression e : oe is translated into an MA( Sigma) expression A[e] unit oe, while ....

O. P. Buneman, R. Nikhil, and R. E. Frankel. An Implementation Technique for Database Query Languages. ACM Transactions on Database Systems, 7(2):164--187, June 1982.

....projections on sets of pairs. ffl pairwith 1 : map(hsnd; fsti) ffi pairwith 2 ffi hsnd; fsti. pairwith 1 is like pairwith 2 , but pairs to the left. ffl cartprod : flatten ffi map(pairwith 1 ) ffi pairwith 2 ffl unnest 2 : flatten ffi map(pairwith 2 ) It is interesting to note that FQL [11], a language designed for the pragmatic purpose of communicating with functional network databases was based roughly on the same set of functional operators. 3.3 Translations between the calculus and the algebra As we mentioned before, expressions in the calculus define functions when we consider ....

P. Buneman, R. E. Frankel, R. Nikhil, An implementation technique for database query languages, ACM Transactions on Database Systems 7, No. 2 (1982), 164--187.

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P. Buneman, R. E. Frankel, and R. S. Nikhil. An implementation technique for database query languages. ACM TODS, 7(2), 1982.

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P. Buneman, R. E. Frankel, and R. S. Nikhil. An implementation technique for database query languages. ACM TODS, 7(2), 1982.

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Buneman, O.P, Frankel, R.E and Nikhil, R., An Implementation Technique for Database Query Languages, ACM Transactions on Database Systems 7, 2 (June 1982), 164-186.

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