... in several rows in Classes for that room. 2.4 Third Normal Form (3NF) Another normal form can address these problems. A table is in Third Normal Form (3NF) if for all X → Y, where ... records in COBOL and other 3GL languages. The birthday and sex information for each child is part of a repeated group, and therefore violates 1NF. This is faking a four-element array in SQL; ... the theory before you use such a tool. 2.1 Functional and Multivalued Dependencies A normal form is a way of classifying a table based on the functional dependencies (FDs for short) in...
Ngày tải lên: 06/07/2014, 09:20
... types that can be compared. Most programmers miss this fact and use it only for numeric values, but it can be used for character strings and temporal data as well. The <high 13.2 OVERLAPS ... Season' 'Santa Claus' 'Year of the Prune' This VIEW is handy for other queries. The reason for using the NOT in the WHERE clause is so that you can add or remove it to reverse ... the student who got 90.001 will argue that he should have gotten an ‘A’ and not a ‘B’, and so forth. This is a problem with a continuous variable. A better solution might be to change the...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P33 pdf
... Today, there is no difference in the three forms in the major products, so the EXISTS(SELECT * ) is the preferred form. Indexes are very useful for EXISTS() predicates because they ... Queries As mentioned before, the list of an IN() predicate can be any scalar expression. This includes scalar subqueries, but most people do not seem to know that this is possible. For example, given ... alone completely. For example, we want to find all employees who were born on the same day as any famous person. The query could be: 14.3 NULLs and the IN() Predicate 293 formulation might...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P42 pdf
... that change more than one column at a time. For example, the following command: UPDATE V5 SET c1 = 0, c2 = 0, c3 = 0, c4 = 0, c5 = 0; will fail for all possible combinations of <levels clause>s ... structures for the VIEW. These structures are usually an array of pointers into a base table 390 CHAPTER 18: VIEWS, DERIVED TABLES, MATERIALIZED TABLES, AND TEMPORARY TABLES structure for the ... the mutating table problem, you can use a VIEW that has a WITH CHECK OPTION to enforce subquery constraints. For example, consider a hotel registry that needs to have a rule that you cannot...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P45 pdf
... required to appear in every term, the form is called a disjunctive normal form. The algorithm to convert any Boolean expression into disjunctive canonical form is a bit complicated, but can be ... with 20 units left over for a total of $1,130.00 in inventory costs. 4. FIFO, which stands for “First In, First Out.” We start by looking at the earliest purchases and work forward through time. ... Q2.and_grp); 420 CHAPTER 19: PARTITIONING DATA IN QUERIES You can retain the COUNT() information to rank candidates. For example, Moe meets both qualifications, while other candidates meet only one...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P50 pdf
... see some SQL products that use LN() for the natural log and LOG10() for the logarithm base ten, and some SQLs that use LOG(<parameter>, <base>) for a general logarithm function. Given ... innermost CASE expression uses a SIGN() function, which returns + 1 for a positive number, −1 for a negative number and 0 for a zero. The SUM() counts the −1 results, 468 CHAPTER 21: AGGREGATE ... (MAX(SUBSTRING(item_name FROM 1 FOR seq_nbr_1 * 10)) || ' ' || MAX(SUBSTRING(item_name FROM 1 FOR seq_nbr_2 * 10)) || ' ' || MAX(SUBSTRING(item_name FROM 1 FOR seq_nbr_3 * 10)) ||...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P72 pdf
... path, then the endpoints of P will have number pairs for each of these greater paths. As a canonical form, the least- numbered pairs are returned for these endpoints. CREATE VIEW PathEndpoints (begin_node_id, ... For a path of length zero, the path endpoints are the same node. If there is more than one path between two nodes, each path will be distinguished by its own distinct set of number pairs for ... about this approach, because I have to decide the maximum number of edges in a path before I start looking for an answer. But this solution will work, and I know that a path will have no more...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P74 pdf
... this in pseudocode: FOR k = 1 TO n DO FOR i = 1 TO n DO FOR j = 1 TO n IF a[i,k] + a[k,j] < a[i,j] THEN a[i,j] = a[i,k] + a[k,j] END IF; END FOR; END FOR; END FOR; CHAPTER 31 ... to Chapter 25 for details on modeling matrices in SQL; in particular, review Section 25.3.3, which deals with matrix multiplication in SQL. For example, Dijkstra’s algorithm for the shortest ... 31: OLAP IN SQL 3. OLTP queries tend to be for simple facts. Data warehouse queries tend to be aggregate relationships that are more complex. For example, an OLTP query might ask, “How much...
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Joe Celko s SQL for Smarties - Advanced SQL Programming P81 pdf
... J. 1983. “Algo- rithms for Computing the Sample Variance: Analysis and Recommenda- tions. The American Statistician 37(3):242-247. ” Welford, B. P. 1962. “Note on a Method for Calculating Corrected ... 557 Boyce-Codd Normal Form (BCNF), 73–75 defined, 74 tables, 73–74 See also Normal forms BYTE data type, 104 C Calculated columns, 373 Calendar auxiliary table, 673–75 data, 675 forms, 674 with ... ftp:// ftp.cs.arizona.edu/tsql/tsql2/sql3/mad146 .pdf. ———. 1996. Adding Transaction Time to SQL/Temporal. Change pro- posal, ANSI X3H2-96-502r2, ISO/IEC JTC1/SC21/WG3 DBL MAD- 147r2. At ftp://ftp.cs.arizona.edu/tsql/tsql2/sql3/mad147 .pdf. Snodgrass,...
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Grammar and vocabulary for cambridge advanced and proficiency part 3 pdf
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Check Your English Vocabulary for Academic English.pdf
... sheet Unit One 9 â A&C Black Publishers Ltd 2007. For reference see Easier English Dictionary for Students (978 07475 6624 3). Don't forget to keep a record of the words and expressions ... possible. For each of the sentences here, choose the best word from a, b or c. 4e – Choose the best word Unit Four 27 â A&C Black Publishers Ltd 2007. For reference see Easier English Dictionary for ... for Students (978 07475 6624 3). 1. The former West Germany tried to __________________ its business approach onto the former East Germany. a. imprint b. enforce c. superimpose 2. In a nuclear power...
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Check Your English Vocabulary for Banking & Finance.pdf
... Steve works for BurgerPlanet. He only earns about £6 ________________. a. for an hour b. an hour c. the hour D. Put the words into the correct columns. All could go into this sentence: 31 For reference ... companies receives a request, it checks for retailer identification, valid card number and card 5 ______________ date. This information is 6 ______________ for security reasons. Similarly, when ... complies with the conditions of the contract. This is a much safer form of payment for the exporter. To be even safer, the exporter can arrange for the bank in his/her country to 5 act as / be "confirming...
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