SQL PROGRAMMING STYLE- P17 pps

... full SQL- 92 you could write a constraint like this: CHECK (NOT EXISTS (SELECT store_nbr FROM JobAssignments WHERE job_type = 99)) GROUP BY store_nbr HAVING COUNT(*) > 1)) But many SQL ... code. Despite the SQL/ PSM and other standards, most vendors implement different trigger models and use their proprietary 4GL language, but, being a fanatic, I want a pure SQL solution....

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

... 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

... 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

... database often does not give the user a choice of precision for many calculations. In fact, the SQL standards leave the number of decimal places in the results of many arithmetic operations to

Ngày tải lên: 06/07/2014, 23:20

... then they are both free to do so. The values have be recorded in the most general data type in the SQL engine, so you use a lot of VARCHAR(n) columns in the EAV model. Now try to put a constraint ... thought about the best way to represent their data. Although this topic is not specifically about SQL style, it gives a foundation for decisions that have to be made in the design of any...

Ngày tải lên: 06/07/2014, 23:20

... the present time might excuse the use of proprietary data types. In 20 years of consulting on SQL programming, I have never found a situation that could not be handled by a basic data type or ... another of the same product. Standard SQL has more than enough data types to model most of the things you will find in the real world. As an example, only the SQL Server/Sybase family has...

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