Date, C.J., A Guide to the SQL Standard, Reading, Mass.: Addison-Wesley, 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....the information of inputs independent of the state, which include: the names of the input variables, the input file name for each input variable, and the number of test cases to be generated. 4 Experiment Chays et al. used a set of simple schema definitions (see Figure 3) which is obtained from [3] in their experiment. In their paper, they did describe a more realistic example of database applications. However, they didn t do their experiment based on that. In our experiment, we chose that realistic application and made some minor modifications to make the specification more precise. The ....

C. Date, H. Darwen. A Guide to the SQL Standard. Addison-Wesley, New York, 1997.

....world so there surely must be an answer somewhere in the literature. When one thinks of the limitations of SQL, its inability to express reachability queries comes to mind, as it is well documented in the literature (in fact, in many database books written for very di erent audiences, e.g. [1,5,7,26]) Let us consider a simple example: suppose that R(Src,Dest) is a relation with ight information: Src stands for source, and Dest for destination. To nd pairs of cities (A; B) such that it is possible to y from A to B with one stop, one would use a self join as follows. SELECT R1.Src, ....

....refer to [2] or some other source on the expressive power of rst order logic, many texts just state that relational algebra, calculus and SQL cannot express recursive queries such as reachability. With this limitation in mind, the SQL3 standard introduced recursion explicitly into the language [7,12]. One would write the reachability query as follows. WITH RECURSIVE TrCl(Src,Dest) AS R UNION SELECT TrCl.Src, R.Dest FROM TrCl, R WHERE TrCl.Dest = R.Src SELECT FROM TrCl This simply models the usual datalog rules for transitive closure: trcl(x; y) r(x; y) trcl(x; y) trcl (x; ....

C. J. Date and H. Darwen. A Guide to the SQL Standard. Addison Wesley, 1997.

....higher level abstractions, the syntax of the GPL might be a similar obstacle. Object relational databases are bloated with features we don t really need [2] 20] Won t relationships with extended semantics, schema modules and other extensions make things look even worse For Date and Darwen [4], orthogonality of language concepts is a key issue: A language is orthogonal, if independent concepts are kept independent and not mixed together in confusing ways. Pitfalls in the orthogonality increase the complexity of the language and reduce its expressive power. In our opinion, careful ....

Date, C.J., Darwen, H.: A Guide to SQL Standard, Addison-Wesley, 1996.

....be presented. DDL statements are not discussed, since their syntax and semantics is identical to their interactive VTQL counterparts. The CONNECT, DISCONNECT BEGIN END DECLARE SECTION statements are also excluded from the discussion, since they are identical to their embedded SQL counterparts ([9]) Each of the SELECT, INSERT, DELETE statements are subdivided into two categories, which will be used in the discussion in section 0: Snapshot transformable statements. This category includes VTQL statements that can be mapped to a single SQL statement. Statements that include operations ....

....whole tuple that is current for the designated cursor. The cursor version of the statement may be used only if the cursor points to an updatable result tuple set. The cases for which a result tuple set is updatable practically depend on the underlying DBMS ( 12] 14] 18] The SQL standard ([9]) specifies a minimal set of queries yielding updatable results (roughly, this includes queries which apply only PROJECT relational algebra operations, with no duplicates removal, on a single base table; joins are permitted but only when expressed via a subquery) but various RDBMSs allow ....

C. J. Date and H. Darwen, "A Guide to the SQL Standard" (third edition), Reading, Massachusetts, Addison-Wesley, 1993.

....that designates the primary key. The number of tuples in a relation r is called the cardinality of the relation, denoted by r . The extension of the relation schemas at a particular point in time is called a database instance (or database) Queries against a database are formulated in SQL [19, 9]. Such queries are typically translated by the DBMS query processing engine into expressions of the relational algebra for the purpose of query optimization and execution. In this paper, we are mainly concerned with providing verification objects for query results where the queries are formulated ....

C.J. Date and H. Darwen. A Guide to the SQL Standard (4th Ed), Addison-Wesley, 1997.

....to real numbers whereas discrete time is considered to be isomorphic to natural numbers or a subset of real numbers. Both views assume that time is linearly ordered. We adopt the discrete concept of time and assume that a temporal domain T is a set of timestamps according to SQL2 standard [5]. So we can treat the corresponding temporal database as a D r r (I V TX,R r r, Rr r) for the four sorted first order language containing a new relation symbol pt TM for every temporal multiversion relation Ri TM and constant symbols for at least all the elements of , V and X (and possible ....

DATE C.J., H. DARWEN, A Guide to the SQL Standard. Third Edition, AddisonWesley, Reading, 1994.

....that phenobarbital may not be given for the first 3 months of the study (Section 9. 0, italics added) In developing a query language to support these predicates in the T HELPER system, we have chosen to create a temporal version of the Structured Query Language (SQL) for relational databases [4], instead of using an internally developed database language. Commercial relational databases and standard query languages (such as SQL) allow researchers to reduce the time of software development, to create portable applications for different hardware platforms, and to support modern ....

....an internally developed database language. Commercial relational databases and standard query languages (such as SQL) allow researchers to reduce the time of software development, to create portable applications for different hardware platforms, and to support modern client server architectures [4]. Our approach to extending the relational model to support temporal queries builds upon the research undertaken by others in the database community [5 7] We first modify the two dimensional relational table to incorporate the temporal dimension of data; then, we specify the types of temporal ....

Date, C.J. A Guide to the SQL Standard. Reading, MA: Addison-Wesley, 1989.

.... for a particular assembly or finding the employees that have all the skills required for a particular project) 2) Language constructs for explicit universal quantification were included in the ODMG standard object query language OQL [Cat96] and are being considered in the SQL3 standardization [Dat97]. 3) As we will show in this paper, queries with universal quantification can be evaluated very efficiently in modern data models that support set multivalued references such as the object oriented model of ODMG [Cat96] or the object relational models [Sto96] Existing work on universal ....

C. J. Date. A Guide to the SQL Standard. Addison-Wesley, Reading, MA, USA, fourth edition, 1997.

....one reason is the fear of missing any relevant documents because of too specific query options. Most services deploy the Boolean retrieval model that can be quite restrictive. Hence, users often start with general searches although they do have certain preferences in mind. In the style of SQL [11] and Preference SQL [12] the UniCats query language is both declarative and provides not only common hard conditions but also soft conditions on the global attributes. Hard conditions qualify a document for the result set. Soft conditions express the preferences of the user and can be used for ....

Date, C., Darwen, H.: A Guide to the SQL Standard. Addison-Wesley, 4th edition, 1997.

....denoted by . A database schema S is a collection of relation schemas R R 1 , Rm . For a database schema S, the extension of the relation schemas at a particular point in time is called a database instance (or database) Queries against a database are formulated in SQL [12, 6]. Such queries are typically translated by the DBMS query processing engine into expressions of the relational algebra for the purpose of query optimization and execution. In this paper we are mainly concerned with providing verification objects for query results where the queries are formulated ....

C.J. Date and H. Darwen. A Guide to the SQL Standard (4th Ed), Addison Wesley, 1997.

....concept of logic databases can serve as a clear and expressive foundation for various kinds of database and knowledge based systems. Rule based languages including negation aggregation or nested term structures offer a modeling power that lies above that of the well known database language SQL [DD97, ISO99, EM99] even with the latest additions allowing e.g. recursive views. Today, the static semantics and the evaluation of queries are well understood. The appropriate handling of dynamic behaviour in this context, however, is still a research issue. Although there exist many different ....

....For a more detailed comparison of work on the field of updates and change, we refer the reader to the survey article by Bonner and Kifer [BK98] 5. 2 The Database Language SQL Today, most database management systems provide a variant of SQL as a data definition and data manipulation language (see [DD97, EM99, ISO99] for descriptions of the SQL standards) The retrieval capabilities, i.e. the SELECT operation, together with the possibility to define views yield a programming environment similar to a classical deductive database system, although the wide spread SQL 92 standard does not allow ....

C. J. Date and H. Darwen. A Guide to the SQL Standard. Addison-Wesley, 4th edition, 1997.

....which guided this project. The choice for this approach has been founded on the consideration that relational database systems enjoy high penetration into a host of application areas. One reason for this success surely is the widespread use of standard database languages such as SQL [SQL86,Date87] SQL can be characterized as an end user oriented, mainly declarative language which plays a central role in the database field, even in spite of its well known deficiencies [Date87] One of the most important restrictions of SQL is its lack of computational completeness [Aho79] So, an ....

....areas. One reason for this success surely is the widespread use of standard database languages such as SQL [SQL86,Date87] SQL can be characterized as an end user oriented, mainly declarative language which plays a central role in the database field, even in spite of its well known deficiencies [Date87] One of the most important restrictions of SQL is its lack of computational completeness [Aho79] So, an important class of systems such as knowledge based systems or decision support systems, but also technical systems demanding special search characteristics [Boud92] are not well supported. ....

C.J. Date: "A Guide to the SQL Standard", Addison-Wesley, Reading, 1987

....we wish to set the order date equal to the employee s hire date. Figure 8.16 shows this query. test= UPDATE salesorder test SET order date = employee.hire date test FROM employee test WHERE salesorder.employee id = employee.employee id AND test salesorder.order date employee.hire date; UPDATE 0 Figure 8.16: UPDATE the order date The FROM clause allows the use of the employee table in the WHERE and SET clauses. While UPDATE can use subqueries to control which data rows are updated, only the FROM clause allows columns from other tables to be used in the SET clause. 8.6 Inserting Data ....

....both INSERTs succeed, or none of them. For a more complicated example, suppose you have a table of bank account balances, and suppose you wish to transfer 100 from one account to another account. This is performed using two queries an UPDATE to subtract 100 from one account, and an UPDATE to add 100 to another account. The UPDATEs should either both complete, or none of them. If the first UPDATE completes but not the second, the 100 would disappear from the bank records. It would have been subtracted from one account, but never added to any account. Such errors are very hard to find. ....

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Date, C.J. A Guide to The SQL Standard, Addison--Wesley

....single timestamp for each historical tuple. The later model assumes continuity of the data, meaning that the data will be valid until its next version s instantiation, and if it is the last version, then it is assumed valid until the current time. Temporal query languages are typically SQL based [Date93], and they differ from regular SQL in the functionality rather than the language constructs. TQUEL [Snod84, Snod93] HQUEL [Tan86a] TSQL [Nav87] TSQL2 [Snod92a, Snod94b, Snod95] and HSQL [Sar90a, Sar90b] are examples of temporal query languages. They provide the capability of composing ....

C. J. Date and Hugh Darwen, "A Guide to the SQL Standard", 3 rd Edition, Addison-Wesley, 1993.

....the change to the value of the operator from the inputs to the operator and their changes. 3. 1 Data Model The underlying data model for which our results about incremental computation are presented is relational algebra, sufficiently extended to be consistent with the SQL query language [DD93] The database relations are typically sets or, less often, multisets. A relation is a multiset when the relation contains one or more copies of the one or more tuples. Obviously, a set is a multiset. Moreover, the results of operations on multisets are themselves multisets. Addressing the ....

C. J. Date and H. Darwen. A Guide to the SQL Standard (Third Edition). Addison-Wesley, 1993.

....are inputs) and reversible control of the query; ffl selection by pointing, not typing; and, ffl immediate and continuous feedback. This approach stands in stark contrast to traditional database query approaches that typically employ formbased interfaces or textual query languages like SQL [25], and in which output is formatted as a tabular list of tuples containing alphanumeric fields. The DQ approach offers many advantages for both novice and expert users, including reduced learning curves, fewer errors, increased levels of understanding, and, not to be ignored, user satisfaction. In ....

....i is the subset of relation R selected by query component i; since R i oe F i R R 0 (oe F 1 R) oe F 2 R) oe Fn R) oe (F 1 F 2 : Fn ) R in relational algebra [22, 139] notation, or: SELECT R. FROM R WHERE Condition1 AND Condition2 AND . AND ConditionN in SQL notation [25]. The exact form of each F i depends on the type of DQ component associated with attribute i. For double ended sliders, for example, F i is of the form: R:A i SliderMin R:A i SliderMax while for frequency distribution histograms with n bars, F i is of the form: R:A i Min 1 R:A i Max 1 ....

C.J. Date and H. Darwen. A Guide to the SQL Standard. Addison-Wesley, 3 edition, 1993.

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Date, C.J., A Guide to the SQL Standard, Reading, Mass.: Addison-Wesley, 1987.

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C. J. Date and H. Darwen. A Guide to the SQL Standard. Addison Wesley, 4th edition, 1997.

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C. J. Date, H. Darwen. A Guide to the SQL Standard. Addison-Wesley 1997.

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C. J. Date and H. Darwen. A Guide to the SQL Standard. Addison-Wesley, 4th edition, 1997.

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C. J. Date and Hugh Darwen. A Guide to the SQL Standard. AddisonWesley, 1993.

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C.J. Date and Hugh Darwen. A Guide to the SQL Standard. Addison-Wesley, Reading, Massachusetts, fourth edition, 1997.

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J. C. Date. A Guide to SQL Standard. Addison Wesley. 1987

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Date, C., and Darwen, A., A Guide to the SQL Standard, Addison Wesley.

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Date, C.J and Darwen, H., A Guide to the SQL Standard, Third Edition, Addison-Wesley Publishing Company, Reading, Massachusetts, 1993.

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