SQL PROGRAMMING STYLE- P24 ppsx

... and Centura (née Gupta) lets you pick which one to use—the worst of both nonstandard worlds! In SQL- 92, you have a choice and can force the order of execution. Either do the predicates after

Ngày tải lên: 06/07/2014, 23:20

Ngày tải lên: 06/07/2014, 23:20

... system, 89–90 Display, 96 Domain-Key Normal Form (DKNF), 62–63 DROP TABLE statement, 67 Dynamic SQL, 168–70 purpose, 168 in stored procedures, 169 E Electronic data interchange (EDI) files,

Ngày tải lên: 06/07/2014, 23:20

... particular SQL products that can suggest indexes based on the actual statements submitted to the SQL engine. Consider using one. 6.9 Avoid Correlated Subqueries Rationale: In the early days of SQL, ... is a SQL/ PSM standard, in the real world, only Mimer and IBM have implemented it at the time of this writing. Instead, each vendor has a proprietary 4GL, such as T -SQL for the Syba...

Ngày tải lên: 06/07/2014, 23:20

... will need for your smallest units . In most SQL implementations, rounding and truncation will improve with more decimal places. The downside of SQL is that precision and the rules for truncation ... that only the allowed values appear in the database . If you have the CREATE DOMAIN feature of SQL- 92, use it to build your scales. Nominal scales would have a list of possible val...

Ngày tải lên: 06/07/2014, 23:20

... There was also a series of articles at: http://www.sqlservercentral.com/columnists/sjones/ codingstandardspart2formatting.asp http://www.sqlservercentral.com/columnists/sjones/ codingstandardspart1formatting.asp ... will see “usp_” for user-defined stored procedures, “trig_” for triggers, and so forth. In MS SQL Server, this is a serious problem, because the prefix “sp_” is used for s...

Ngày tải lên: 06/07/2014, 23:20

... programmers. My goals in this book are to improve SQL programming style and proficiency. To be more exact: 1. To help an individual programmer write Standard SQL without an accent or a dialect . ... other SQLs, cannot be easily understood by an end user, and cannot be expanded. In the second case, what some newbies, who are still thinking in terms of second- and third-generati...

Ngày tải lên: 10/04/2014, 09:40

... tables, 63 SQL 4GLs, 151, 152 bad programming in, 184–89 as declarative language, 193 Dynamic, 168–70 injection, 169–70 Standard, 4, 5, 6, 7, 118 testing, 130–31 thinking in, 183–95 SQL- 92 CASE ... 3 quoted identifiers, 5 string operators, 108 SQL- 99, 3 Stamp coupling, 156 Standard functions, 108 Standard Industrial Classification (SIC), 14 Standard SQL case-sensitivity rules, 6, 7...

Ngày tải lên: 06/07/2014, 23:20

... about Student Programming Practices,” Structured Programming , Fall 1989, p. 215. Celko, J. SQL for Smarties (3rd ed.). San Francisco: Morgan-Kaufmann, 2005. Celko, J. SQL Puzzles ... of Programming Style . Boston: McGraw-Hill, 1982. Ledgard, H. Programming Prover bs. Rochelle Park, NJ, Hayden Books, 1975. Ledgard, H., and L. J. Chmura. Fortran with Style:...

Ngày tải lên: 06/07/2014, 23:20

... the count is redundant; SQL is orthogonal, and the scalar subquery can be used wherever the scalar variable is used. Rows are not records and columns are not fields. SQL is a declarative language, ... TIMESTAMP,—null means current CHECK(in_time < out_time), PRIMARY KEY (user_id, in_time)); Many new SQL programmers are scared of NULLs, but this is a good use of them. We do not...

Ngày tải lên: 06/07/2014, 23:20