J. Melton. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 2 edition, 2000.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....encodings. It should be noted that the UTF 8 encoding preserves ASCII encoding, while tripling the size of Indic strings from their proprietary ISCII encoding. The UTF 16 encoding doubles the size of data for both ASCII and ISCII strings. 3. 2 What does the SQL Standard offer Until the SQL 92 [12] standard, there was not much support specified in relational databases for languages other than English, which was assumed as a default. However, in late eighties the need for supporting multiple character sets was recognized and specifications were introduced in the standard to overcome this ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, San Francisco, California, 1993.

....The purpose of the various lock modes are shown alongside. Serializability Concepts and the Phantom Problem Transactions, locking and serializability concepts are well documented in the literature [112, 113, 55] The phantom problem is defined as follows (from the ANSI ISO SQL 92 specifications [93, 7]) Transaction T1 reads a set of data items satisfying some search condition . Transaction T2 then creates data items that satisfy T1 s search condition and commits. If T1 then repeats its scan with the same search condition , it gets a set of data items (known as phantoms ) different from ....

J. Melton and A. R. Simon. Understanding the new sql: A complete guide. Morgan Kauffman, 1993.

....and inclusion dependencies are the ones used most often. More precisely, only two subclasses of functional and inclusion dependencies, namely, keys and foreign keys, are commonly found in practice. Both are fundamental to conceptual database design, and are supported by the SQL standard [30]. They provide a mechanism by which one can uniquely identify a tuple in a relation and refer to a tuple from another relation. They have proved useful in update anomaly prevention, query optimization and index design [1; 37] XML (eXtensible Markup Language [6] has become the prime standard for ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....temporal databases (cf. OS95] spatiotemporal databases (cf. Wor94] and active temporal databases. Finally, the ideas presented here and the methodology that will follow should be transitioned to existing implementation platforms, including non temporal query languages such as SQL 92 [MS93] In the short and perhaps even medium term, it is unrealistic to assume that applications will be designed using a temporal data model, implemented using novel temporal query languages, and run on as yet nonexistent temporal DBMSs. 43 5 Acknowledgments We would like to thank Jim Clifford, ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1993.

....functional and inclusion dependencies are the ones used most often. More precisely, only two subclasses of functional and inclusion dependencies, namely, keys and foreign keys, are commonly found in practice. Both are fundamental to conceptual database design, and are supported by the SQL standard [30]. They provide a mechanism by which one can uniquely identify a tuple in a relation and refer to a tuple from another relation. They have proved useful in update anomaly prevention, query optimization and index design [1; 37] XML (eXtensible Markup Language [6] has become the prime standard for ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....data structures is the Partially Ordered Set (POSET) 6] which is used in applications such as livestock, corporate management, company divisions, manufacturing, literature, ideas, evolution, scientific research and theory. Unfortunately, SQL (Structured Query Language) and its numerous extensions [7, 8] do not effectively support hierarchical data structures in relational databases. In Oracle, hierarchical data is represented as the collection of relational tables. We are able to query POSET data using the CONNECT BY clause of SQL [9] to search for hierarchical relationships presented by the ....

J. Melton and A.R. Simon, "Understanding the New SQL: A Complete Guide",Morgan Kaufmann, San Francisco, CA, 1993.

....(20) 3.3 Null Values In this subsection, we will revisit our equivalences under the aspect of unknown attribute values. The ODMG standard [Cat96] addresses null values only for object references (nil references) Since null values are, however, integral part of SQL, we will assume SQL semantics [MS93] for null values, i.e. we use a three valued logic with a third value unknown. In this three valued logic the truth value of (trueunknown) is unknown, of (falseunknown) is false, of (trueunknown) is true, of (falseunknown) is unknown, and ( unknown) is unknown. An object qualifies for a subquery ....

J. Melton and A. R. Simon. Understanding the new SQL: a complete guide. Morgan-Kaufmann Publishers, San Mateo, CA, USA, 1993.

....[16, 13, 21] It appears, therefore, that the distinction between types and constraints is dictated largely by what conventional programming languages treat as types. That there is a non trivial interaction between types and constraints is evident from consideration of the following SQL [20] specification: create table students ( SSN char(9) name char(20) primary key (SSN) create table courses ( cno char(7) 1 r courses name SSN cno title SSN DB 234 Kate CS 331 234 123 Greg 123 CS 331 ( a ) r students students courses CS 331 DB 123 Greg ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....which then encode a time interval. Many of the tuples in a database typically record facts that apply to a time interval that stretches from some past time to the current time, prompting a need for a time value that denotes the current time in the to time attribute of these tuples. While SQL 92 [22] includes the datetime value functions CURRENT DATE, CURRENT TIME, and CURRENT TIMESTAMP, these functions cannot be stored directly as values of attributes in relations. In the absence of a current time value in SQL s DATE, TIME, and TIMESTAMP domains or in the corresponding domains offered by ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers 1993. 33

....functional and inclusion dependencies are the ones used most often. More precisely, only two subclasses of functional and inclusion dependencies, namely, keys and foreign keys, are commonly found in practice. Both are fundamental to conceptual database design, and are supported by the SQL standard [30]. They provide a mechanism by which one can uniquely identify a tuple in a relation and refer to a tuple from another relation. They have proved useful in update anomaly prevention, query optimization and index design [1, 37] XML (eXtensible Markup Language [6] has become the prime standard for ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....String register University String name integer semesterFee 0. n 1 member Figure 2 Sample UML model According to the usual class to table mapping [3] we have to generate a relational database schema with three tables. The most important part of a relational database schema defined by SQL [15] are definition statements for the tables (CREATE TABLE) plus referential constraints for the mapping of class relationships (inserted by ALTER TABLE) CREATE TABLE Student (OID INTEGER PRIMARY KEY, suspended BOOLEAN, register VARCHAR(255) OID University INTEGER NOT NULL) ALTER TABLE Student ....

Melton, J., Simon, A., Understanding the New SQL:A Complete Guide, Morgan Kaufmann, 1993

....advantage that the rules cannot be circumvented by ad hoc operations on the DBMS. Several commercial DBMS products and research prototypes provide facilities like trigger mechanisms and stored procedures for rule integration. Some types of integrity constraints are already defined in SQL2 [6]; the SQL3 standard will presumably also provide constructs for defining triggers. The appearance of more active DBMS will offer a higher potential for enforcing rules by DBMS as currently available systems. Independent of the power of existing and forthcoming commercial DBMS products, a ....

Melton, J., Simon, A.R., Understanding the New SQL: A Complete Guide, Morgan Kaufmann, San Mateo 1993.

....may be assigned a timestamp in the midst of its data accesses. So a transaction can change from one without a timestamp to one with a timestamp at any time. This is important in our effort to delay the choice of timestamp. Only when a request for the current time, e.g. CURRENT TIME in SQL [10], is made are we compelled to assign a timestamp prior to commit. Otherwise, we can wait until transaction commit, at that time assigning a timestamp that agrees with transaction conflict order. Monotonically increasing timestamps in which the timestamp assigned is greater than all previously ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993.

....model and OQL query language [4] are used for the ODBs) The paper s contribution is presented in terms of the SumQL and SumQL languages, which are defined formally in the paper and concisely capture the relevant concepts, to be self contained and ensure precision. Other languages such as SQL [23], OQL [4] and MDX [24] may take the place of SumQL once enriched with the constructs in SumQL that they do not already offer. Additionally, the approach can easily be extended to allow queries over external relational databases that allow path expressions in queries, e.g. as proposed in the ....

J. Melton and A. R. Simon. Understanding the new SQL - A Complete Guide. Morgan Kaufmann, 1993.

....preserving the standard operator precedence. Parentheses are used to override this precedence. The grammar incorporates the possibility of using unary and binary functions (f and g, respectively) belonging to some function library (e.g. the standard functions normally used in relational DBMSs [21]) 0 EXPR 1 2 0 EXPR1 0 TERM1 0 EXPR1,3 0 TERM1 0 TERM 1 0 TERM 2 0 TERM1 4 0 FACTOR15 0 TERM176 0 FACTOR1 0 FACTOR 0 FACTOR1 298 0 EXPR1; 5 f 8 0 EXPR1 :5 g 0 EXPR1= 0 EXPR1 : The terminal symbol is a metavariable defined as: ACB AttributeList[att ....

Melton, J. et. al. Understanding the New SQL: A Complete Guide, Morgan-Kaufmann, 1995

....the paper we enforce that all the ATSQL temporal relations are coalesced. The timestamps are represented by maximal non overlapping periods. This is fundamental for our translation of temporal logic queries to ATSQL to work correctly. ATSQL Queries. ATSQL extends the query language of SQL 92 [Melton and Simon 1993]. The crucial concepts in ATSQL are statement modifiers (or flags) that can be prepended to queries to modify their temporal behavior . As a consequence ATSQL queries come in three flavors (in the rest of the paper we underline the ATSQL specific additions to SQL) 1) SQL 92 queries (without ....

Melton, J. and Simon, A. R. 1993. Understanding the new SQL: A Complete Guide. Morgan Kaufmann Publishers.

....may be assigned a timestamp in the midst of its data accesses. So a transaction can change from one without a timestamp to one with a timestamp at any time. This is important in our effort to delay the choice of timestamp. Only when a request for the current time, e.g. CURRENT TIME in SQL [10], is made are we compelled to assign a timestamp prior to commit. Otherwise, we can wait until transaction commit, at that time assigning a timestamp that agrees with transaction conflict order. Monotonically increasing timestamps in which the timestamp assigned is greater than all previously ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993.

....rights appropriate to relational databases, e.g. select, insert, update, delete, etc. of tuples by relation, package, index or view name. The ability of users to grant and revoke privileges on database relations to other users is part of the query language interface, and is part of the standard [MS93]. It is also typical of relational databases to store the relation descriptions and privileges in relations which are readable by SQL SELECT statements. The names of these relations are not part of the standard, and di er from one implementation to the next [MS93] We do not consider mandatory ....

....and is part of the standard [MS93] It is also typical of relational databases to store the relation descriptions and privileges in relations which are readable by SQL SELECT statements. The names of these relations are not part of the standard, and di er from one implementation to the next [MS93]. We do not consider mandatory access control in this paper. The rest of the paper describes two experiments. The rst one involved taking a tool which allows role graphs to be speci ed, and mapped the resulting userprivilege pairs onto a relational database package. The second went in the other ....

Jim Melton and Alan R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993.

....integrity constraint that must hold for each row of a table, DOMAIN creates a (restricted) column domain, and ASSERTION defines a named, general integrity constraint that may refer to more than one table. In fact, these keywords have already been defined in SQL 92 (also known as SQL2) [50, 20]. The following example illustrates the usage of these keywords. Example 1. Suppose in our sample application domain, we have to manage information about employees. Employees are uniquely identified by an artificial id. We assume that every employee has a first name and a last name. Every ....

....we have provided general guidelines for the design and implementation of integrity constraints using the mechanisms and functionality provided by these systems. In summary, our observation is that current commercial database management systems basically support the entry level of SQL 92 [50, 20]. This means that with regard to the specification of declarative constraints these systems support the specification of default values, not null constraints, primary and foreign keys, uniqueness constraints, and check constraints on the column level. Some systems support the specification of ....

J. Melton and A. R. Simon. Understanding the New SQL --- A Complete Guide. Morgan Kaufmann Publishers, San Mateo, CA, 1993.

....can be built. Typically, nldbs have used an intermediate representation language (usually some form of logic) to encode the meanings of natural language requests, with the resulting intermediate language expressions being available for translation into a suitable database language, often sql (Melton Simon 93) The benefits of this include generality, modularity, portability (Androutsopoulos et al. 95b) Building on this architecture, we propose a framework for constructing nldbs for temporal databases (nltdbs) that draws on ideas from tense and aspect theories (see (Comrie 76) and (Comrie 85) for ....

....to determine the particular times to which adverbials like at 5:00pm or verb tenses refer. 5 The TSQL2 language We now turn to tsql2, the database language into which we translate the top formulae that the linguistic processing generates. tsql2 (Snodgrass 95) is a temporal extension of sql (Melton Simon 93) the de facto standard database language. Traditional database languages such as sql can and have been used to handle temporal information, leading some researchers to question the need for special temporal support in database languages (see (Davies et al. 95) for related discussion) The lack ....

J. Melton and A.R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, San Mateo, California, 1993.

....shows that when the system assigns default valid time values, valid time must be handled identically to transaction time. Otherwise, the user can extract database states that are inconsistent. When the CURRENT DATE function (as well as the associated CURRENT TIME and CURRENT TIMESTAMP functions [16]) is present, we show that the value returned must be the commit time of the transaction. It turns out that the use of the commit time may lead to (illegal) periods that start after they end. When this occurs, the intermediate result of a modification, computed during the execution of the ....

.... 1998 01 23 Joe Outdoor 1998 01 08 nobind now 1998 01 23 until changed Table 1: The Bitemporal Table, Emp A number of quite different and more or less temporally enhanced query languages exist that permit an application programmer to modify and query bitemporal tables [31] For example, SQL 92 [16] and SQL3 provide little built in support, leaving more work to the application programmer. Other languages such as TSQL2 [22] and ATSQL [3] extend SQL 92 and provide advanced support, making application development easier. Using an integrated DBMS architecture to implement a temporal data model ....

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J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, 1993.

....the two operands cannot be coerced into comparable types. OEMNil is used to implement three valued logic for mixed boolean expressions. Mixed boolean expressions are evaluated in OQL S according to the rules of three valued logic, similar to Lorel and just as NULL values are treated in SQL [MS93] There are two important aspects to the use of OEMNil for implementing three valued logic: First, if the Where clause of a query is a mixed boolean expression, a value of OEMNil for the Where clause is interpreted as false. Second, if a query returns a collection of OEM objects, any OEMNil ....

J. Melton and A.R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, San Francisco, California, 1993.

....developed for relational databases, functional and inclusion dependencies are the only ones that are commonly used in practice. More precisely, only two subclasses of functional and inclusion dependencies, namely, keys and foreign keys, are still being widely used and supported by the SQL standard [23]. Keys and foreign keys are fundamental to conceptual database design. They provide a mechanism by which one tuple may refer to another tuple. They are also useful in update anomaly prevention, query optimization and index design [1, 30] Keys and foreign keys have been proposed for XML in, e.g. ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....Aggregate Selection Suppose we wish to locate organizational units in AT T that directly employ more than 10000 persons. Although LDAP queries cannot express selections based on aggregate conditions, the useful role played by aggregation in query languages such as SQL (see, for example, [12]) suggests the desirability of supporting marking operators involving aggregation. Our structural aggregate selection operators directly extend each of the hierarchical location operators by adding an extra argument that captures the aggregate selection condition. For example, the above query can ....

J. Melton and A. R. Simon. Understanding the new SQL: A complete guide. Morgan Kaufmann, San Francisco, CA, 1993.

....formalisms were developed for relational databases, functional and inclusion dependencies are the ones used most often. More precisely, only two subclasses of functional and inclusion dependencies, namely, keys and foreign keys, are commonly found in practice and are supported by the SQL standard [31]. Keys and foreign keys are fundamental to conceptual database design. They provide a mechanism by which one can uniquely identify a tuple in a relation and refer to a tuple from another relation. They have proved useful in update anomaly prevention, query optimization and index design [1, 39] ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

....confusing but also challenging variety of alternatives. As one response to this state of affairs, a committee of eighteen temporal database researchers has recently released the TSQL2 Language Specification [SAA 94a] which defines a temporal extension to the SQL 92 standard [SQL92, MS93] TSQL2 was created partly in an attempt to consolidate, in a single consensual model and language, the insights and experiences gained from the development of the previous data models and languages. As a quite different approach, other efforts (e.g. CCT93, CCT94, MS91, Boh94, BM94] have put ....

....valid time query to appear in a larger query everywhere a valid time relation name may appear, so that if the valid time query computes the named relation, the two forms of the larger queries compute the same result. This feature is provided by table expressions, which were introduced in SQL 92 [MS93, p.178] and carried over to TSQL2. The fourth requirement is satisfied by the where clause which is enhanced with temporal predicates that have the same expressive power as Allen s predicates. Temporal attributes of base relations, implicitly computed valid times (e.g. valid times computed by ....

J. Melton and A. R. Simon. Understanding the new SQL: A Complete Guide. Morgan Kaufmann Publishers, 1993.

....it would be quite useful to be able to store a variable, such as now , to indicate that the time when a balance is valid depends on the current time. In the example, it would be recorded on January 15 that the customer s balance of US 200 is valid from January 15 through now . While SQL 92 [Melton and Simon 1993] has a construct CURRENT TIMESTAMP (as well as CURRENT DATE and CURRENT TIME) for use in queries, one cannot store such a value in a column of an SQL table. All major commercial DBMSs have similar constructs, and impose this same restriction. The user is forced instead to store a specific time, ....

.... [Snodgrass 1987, Snodgrass 1993, Ben Zvi 1982, Thirumalai and Krishna 1988] instead of now . These symbols (we will use forever) denote the largest representable timestamp value, that is, the one furthest in the future. In SQL and in IBM s DB2, forever is about 8,000 years from the present [Melton and Simon 1993, Date and White 1990] in our more liberal proposal, it is approximately 18 billion years from the present time [Dyreson and Snodgrass 1993a] By using a to time of forever , as in Figure 1(b) we certainly avoid the pessimistic assumption, but we are now being overly optimistic. We have ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1993.

....design needs to be explored in greater detail. The methodology should be validated with actual applications. Finally, the ideas presented here and the methodology that will follow should be transitioned to existing implementation platforms, including non temporal query languages such as SQL 92 [MS93] In the short and perhaps even medium term, it is unrealistic to assume that applications will be designed using a temporal data model with new design methodologies, implemented using new temporal query languages, and run on new temporal DBMSs. 5 Acknowledgments We would like to thank Jim ....

J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1993.

....1, x) from W when x = 2 is not satis ed. The triggering events are the update of variable x. The rules are given below, where variables are used in the SQL queries: 2 Although variables are not supported in SQL2 operations, it is very likely that support for variables will be provided in SQL3 [15]. SQL3 is expected to provide support for combining relations and objects [14] 7 T 1 A B a b c b d e T 2 B C a d e a A (T 1 1 T 2 ) A d T 0 1 A B a e c a d e A (T 0 1 1 T 2 ) A a c Figure 3: Maintaining a view in response to a modi cation of the base data T V 1 A ....

Jim Melton and Alan R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, San Mateo, CA, 1993. 13

.... designs of spatial algebras with formal semantics are given in [SV89, GNT91, GS95] Perhaps in part because of the pervasiveness of time and their simpler structures, time types are already supported by existing database systems, and the SQL standard offers types such as DATE, TIME, and TIMESTAMP [MS93] In the research domain, semantic foundations for interpreting time values [Sno95, Ch. 5] and efficient formats [Sno95, Ch. 25] for storing time values have been proposed [DS94] as has extensible, multi cultural support, including support for multiple languages, character sets, time zones, and ....

Jim Melton and Alan R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, 1993.

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J. Melton and A. R. Simon, "Understanding The New SQL: A Complete Guide," Morgan Kaufmann 1993.

....can unnecessarily overload Web servers (especially if users are interested in a small subset of the data) Furthermore, accessing a particular record within a big file can be rather cumbersome. The alternative of giving direct access to the databases through expressive query languages such as SQL [4] or XML QL [2] is not practical, as these languages are too complex for casual Web users. Form interfaces are thus a good choice as they provide a very simple way to query (and filter) data. Simplicity however, comes at a price. Form interfaces can be quite restrictive, disallowing interesting ....

J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993.

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J. Melton. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 2 edition, 2000.

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J. Melton and A. R. Simon. Understanding the new SQL: A complete guide. Morgan Kaufmann, San Francisco, CA, 1993.

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Melton, J., Simon, A., Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993

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J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, Inc., San Mateo, CA, 1993.

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Melton, J., Simon, A.: Understanding the New SQL: A Complete Guide. Morgan Kaufmann, 1993 13 Melton, J., Simon, A., R., Gray, J.: SQL:1999 - Understanding Relational Language Components. Morgan Kaufmann Publishers, 2001 14 Momotko, M., Subieta. K.: Dynamic change of Workflow Participant Assignment, ADBIS'2002, Bratislava, Slovakia

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J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann, San Francisco, California, 1993.

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J. Melton and A. R. Simon. Understanding the new SQL: A Complete Guide. Morgan Kaufmann, 1993.

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J. Melton and A. R. Simon. Understanding the new SQL - A Complete Guide. Morgan Kaufmann, 1993.

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J. Melton and A. R. Simon. Understanding the new SQL: A Complete Guide. Morgan Kaufmann, 1993.

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Jim Melton, Alan R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufmann Publishers, Inc., 1994.

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J. Melton and A. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993.

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J. Melton and A. R. Simon. Understanding the New SQL: A Complete Guide. Morgan Kaufman, 1993. ISBN 1-55860-245-3.

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J. Melton and A. R. Simon. Understanding the new SQL: A complete guide. Morgan Kaufmann, San Francisco, CA, 1993.

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Melton, Jim, & Alan, Simon R. "Understanding the New SQL: A Complete Guide," Morgan Kaufmann Publishers, San Francisco, CA, 1993. 53

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Jim Melton and Alan Simon, Understanding the New SQL: A Complete Guide, Morgan Kaufmann, San Francisco, CA, 1993.

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J. Melton, and A.R. Simon, Understanding the New SQL: A Complete Guide, Morgan Kaufmann, San Francisco, 1993.

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Melton, J. and Simon, A.R. 1993. Understanding the New SQL: A Complete Guide. San Francisco, CA: Morgan Kaufmann.

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J. Melton and A. R. Simon. Understanding the new SQL: A Complete Guide. Morgan Kaufmann Publishers, San Mateo, California, 1993.

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