G. Grahne and E. Waller. How to make SQL stand for string query language. In R. Connor and A. Mendelzon, editors, Research Issues in Structured and Semistructured Database Programming. Proceedings of the 7th International Workshop on Database Programming Languages, DBPL'99, volume 1949.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....may return an infinite number of strings. This is the standard issue of safety. Previous proposals for combining relational algebra with string matching primitives tackle this problem by identifying safe fragments of their languages, using a number of syntactic restrictions see, e.g. [39, 42, 38, 40, 59] but they cannot capture the safe fragment of the language syntactically. A second issue with any string query language is its expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and ....

....fragment of the language syntactically. A second issue with any string query language is its expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and optimization impossible. Indeed, as noted in [40], adding just concatenation to the relational calculus already yields a query language which is Turing complete. This immediately implies that there is no effective syntax for the corresponding safe fragment [64] In contrast to the above, we would like our languages to fulfill the following ....

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G. Grahne, E. Waller. How to make SQL stand for string query language. In Proceedings of DBPL'99, Springer LNCS vol.

....may return an in nite number of strings. This is the standard issue of safety. Previous proposals for combining relational algebra with string matching primitives tackle this problem by identifying safe fragments of their languages, using a number of syntactic restrictions see, e.g. [39, 42, 38, 40, 59] but they cannot capture the safe fragment of the language syntactically. A second issue with any string query language is its expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and ....

....fragment of the language syntactically. A second issue with any string query language is its expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and optimization impossible. Indeed, as noted in [40], adding just concatenation to the relational calculus already yields a query language which is Turing complete. This immediately implies that there is no e ective syntax for the corresponding safe fragment [64] In contrast to the above, we would like our languages to ful ll the following ....

[Article contains additional citation context not shown here]

G. Grahne, E. Waller. How to make SQL stand for string query language. In Proceedings of DBPL'99, Springer LNCS vol. 1949.

....in data representation and manipulation for genome or text databases, where much of the data has an inherently sequential structure. Numerous formalisms involving sequences and sequence variables, like Sequence Logic ( 11] Alignment Logic ( 12] Sequence Datalog ( 20] String Calculus ([13], 3] have been developed for this field. Rewriting variable arity symbols used in rewriting usually come from flattening terms with associative top function symbol. Sequences and sequence variables (sometimes called also patterns) which are used together with variable arity symbols, make ....

G. Grahne and E. Waller. How to make SQL stand for string query language. Lecture Notes in Computer Science, 1949:61--79, 2000.

....[11, 12] considered Datalog extended with appropriate transducers for string operations, proving a number of completeness results. In [14] arbitrary regions (substrings) can be queried; this, when coupled with relational calculus, gives the power of string concatenation. Closer to our approach, [20, 26] study the relational calculus algebra extended with an operation for concatenating strings. 15] studies rst order logic over term algebras and extends expressive bounds and complexity results from relational calculus to this setting. But SQL style string pattern matching cannot be expressed in ....

....queries with relational calculus is that pattern matching expressions may return an in nite number of strings. This is the standard issue of safety. The authors tackle this problem by identifying safe fragments of their languages, using a number of syntactic restrictions see, e.g. [19, 22, 18, 20, 26] but they cannot capture the safe fragment of the language syntactically. A second problem concerns expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and optimization impossible. Indeed, as ....

[Article contains additional citation context not shown here]

G. Grahne, E. Waller. How to make SQL stand for string query language. In DBPL'99.

....[11, 12] considered Datalog extended with appropriate transducers for string operations, proving a number of completeness results. In [14] arbitrary regions (substrings) can be queried; this, when coupled with relational calculus, gives the power of string concatenation. Closer to our approach, [19, 27] study the relational calculus algebra extended with an operation for concatenating strings. One problem faced in all this work is that queries that manipulate string languages may return an in nite number of strings. This is the standard issue of safety. The authors tackle this problem by ....

....problem faced in all this work is that queries that manipulate string languages may return an in nite number of strings. This is the standard issue of safety. The authors tackle this problem by identifying safe fragments of their languages, using a number of syntactic restrictions see, e.g. [18, 21, 17, 19, 27] but they cannot capture the safe fragment of the language syntactically. A second problem concerns expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and optimization impossible. Indeed, as ....

[Article contains additional citation context not shown here]

G. Grahne, E. Waller. How to make SQL stand for string query language. In DBPL'99.

....[11, 12] considered Datalog extended with appropriate transducers for string operations, proving a number of completeness results. In [14] arbitrary regions (substrings) can be queried; this, when coupled with relational calculus, gives the power of string concatenation. Closer to our approach, [19, 27] study the relational calculus algebra extended with an operation for concatenating strings. One problem faced in all this work is that queries that manipulate string languages may return an infinite number of strings. This is the standard issue of safety. The authors tackle this problem by ....

....problem faced in all this work is that queries that manipulate string languages may return an infinite number of strings. This is the standard issue of safety. The authors tackle this problem by identifying safe fragments of their languages, using a number of syntactic restrictions see, e.g. [18, 21, 17, 19, 27] but they cannot capture the safe fragment of the language syntactically. A second problem concerns expressive power. Many query languages designed in the prior literature turn out to be Turing complete, a feature that in turn makes many sorts of analysis and optimization impossible. Indeed, ....

[Article contains additional citation context not shown here]

G. Grahne, E. Waller. How to make SQL stand for string query language. In DBPL'99.

....solution. However, in other cases, such as genome databases and text databases, there is still a need for more flexibility in data representation and manipulation. The problem of extending relational databases with string manipulation features has recently motivated several research proposals [4, 8, 5, 6, 7]. In fact, sequences represent a particularly interesting domain for query languages. In contrast to sets, computations over sequences can easily become infinite, even when the underlying alphabet is finite. This is because repetitions of symbols are allowed, so that the number of possible ....

G. Grahne and E. Waller. How to make SQL stand for String Query Language ? In Seventh Intern. Workshop on Database Programming Languages (DBPL'99), Kinloch Rannoch, Scotland, 1999.

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G. Grahne and E. Waller. How to make SQL stand for string query language. In R. Connor and A. Mendelzon, editors, Research Issues in Structured and Semistructured Database Programming. Proceedings of the 7th International Workshop on Database Programming Languages, DBPL'99, volume 1949.

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