SQL PROGRAMMING STYLE- P43 pps

... 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

... SQL Server Audit combine to produce an output that is called an audit. The SQL Server Audit feature in SQL Server 2008 is intended to replace SQL Trace as the preferred auditing solution. SQL ... Compliance SQL Server Auditing Introduced with SQL Server 2008 is the SQL Server Audit feature. This long-overdue feature now adds a great native auditing functionality into the S...

Ngày tải lên: 05/07/2014, 02:20

... ORDER BY clause is part of a cursor, not part of a SELECT statement. Because some SQL products, such as SQL Server and Sybase, allow the user to create implicit cursors, many newbies get ... committed or rolled back, possibly causing resource contention on the server. In Standard SQL, there is an SQLSTATE code that tells you if the result set of a GROUP BY has members that exclu...

Ngày tải lên: 06/07/2014, 09:20

... 108 CHAPTER 3: NUMERIC DATA IN SQL 3.3 Four-Function Arithmetic SQL is weaker than a pocket calculator. The dyadic arithmetic operators +, −, ... an expression that worked one way in the host language may get different results in SQL, and vice versa. SQL could reorder the expressions to optimize them, but in practice, you will find ... your SQL. The monadic plus and minus signs...

Ngày tải lên: 06/07/2014, 09:20

... you have to say (x IS [NOT] NULL) in SQL and not use (x = NULL) instead. Table 6.1 shows the tables for the three operators that come with SQL. Table 6.1 SQL s Three Operators x NOT ================== TRUE ... criticisms apply to any system that supports SQL- style NULL s, not just to SQL Server specifically.)” 182 CHAPTER 5: CHARACTER DATA TYPES IN SQL d. SCH =>...

Ngày tải lên: 06/07/2014, 09:20

... equal to” in some older SQL implementations. These symbols are borrowed from the C and PL/I programming languages, respectively, and have never been part of standard SQL. It is a bad habit ... test to see if an expression is NULL or not, and it has been in SQL- 86 and all later versions of the standard. The SQL- 92 standard extended it to accept <row value constructor&g...

Ngày tải lên: 06/07/2014, 09:20

... READ ONLY. The ORDER BY and CASE Expressions SQL- 99 allows you to use a function in an ORDER BY clause. While it is now legal, it is still not a good programming practice. Users should see the ... different in syntax, or semantics, or both. Today, they are all gone and replaced by the Standard SQL syntax. In the second edition of this book, I described the proprietary extensions i...

Ngày tải lên: 06/07/2014, 09:20

... the Database System Standard SQL requires a system schema table with the text of the VIEW declarations in it. What would be handy, but is not easily done in all SQL implementations, is to trace ... Practical” (Goodman 1990): 1. Projection from a single table (Standard SQL) 2. Restriction/projection from a single table (Standard SQL) 3. UNION VIEWs 4. Set difference VIEWs 5. One-to...

Ngày tải lên: 06/07/2014, 09:20

... CHAPTER 19: PARTITIONING DATA IN QUERIES programming languages. You must know the cost in execution time for your product before doing this. One version of SQL uses a threaded- code approach to ... results on each row—the execution time is horrible. Some versions of SQL can compile and link another language’s library into the SQL. Although this is a generalization, the safest tec...

Ngày tải lên: 06/07/2014, 09:20

... that most new SQL programmers do this in other SQL products is produce a result with an ORDER BY clause, then read the first so many rows from that cursor result. In Standard SQL, cursors have ... which one runs faster on your particular SQL product. If you want to swap the subquery and the constant for readability, you may do so in SQL, but not in SQL- 89. What if I want to al...

Ngày tải lên: 06/07/2014, 09:20