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SQL Server Best Practices in Indian style by Rajat Jaiswal
- 1. SQL Best Practices SQL SERVER BEST PRACTICES IN INDIAN STYLE
- 2. Indiandotnet – Microsoft user group community Rajat Jaiswal http://indiandotnet.wordpress .com HTTPS://facebook.com/indian dotnet
- 3. Is this our AGENDA? BEST PRACTICES IN SQL SERVER
- 4. Bada hai To better Hai Indian mentality but do not apply in database designing (Best Practices in Designing )
- 5. Column Name Data Type (current Data type) Length Data Type(after change) Length EnrollmentHistoryId numeric 9 numeric 9 EnrollmentId numeric 9 numeric 9 ClassId numeric 9 tinyint 1 WorkSheetId numeric 9 int 4 classTeacherId numeric 9 int 4 ClassRoomId numeric 9 tinyint 1 centerId numeric 9 tinyint 1 HomeAddressId nchar 20 int 4 FriendsId numeric 9 int 4 Comments varchar 300 varchar 300 Notes varchar 300 varchar 0 CreatedBy numeric 9 int 4 CreatedDate datetime 8 small datetime 4 ModifiedBy numeric 9 int 4 ParentId numeric 9 numeric 9 ModifiedDate datetime 8 datetime 8 StatusId numeric 9 tinyint 1 SynchStatusId numeric 9 tinyint 1 Rows 753 368 No of rows in curernt database 5000000 bytes 3765000000 1840000000 KB 3676757.81 1796875 MB 3590.5838 1754.76074 GB 3.506429 1.71363354 space diffrence (GB) (aprox) 1.79279596 * above result is by just sum of max length ofvariable & non variable columns
- 7. Are Ye bhi Yaad rakho NULL hi to Hai It is not only about NULL but all the constraints - thik hai / chalta hai - Indian attitude
- 9. I LOVE “ Not IN” MUZE TO SIRF NOT IN CLAUSE EASY LAGTA HAI - TRY JOIN AND OTHER FEATURES ALSO . ALTHOUGH IT NOT ALWAYS BAD
- 10. “ ” Let see demo
- 11. REASON To Think
- 12. SAB AANE DO kaha paise lag rahe hai Free me sab chalega BAAD ME DEKH LENGE ATTITUDE NO FILTER CLAUSE
- 13. “ ” Let see demo
- 14. REASON To Think
- 15. HAR SLOW QUERY KA ILLAGE HAI MERE PASS INDEX HAI MERE PASS PERFORMANCE WILL BE IMPROVE BY INDEX ?
- 16. “ ” Let see demo
- 17. REASON To Think
- 18. FUNCTION HI FUNCTION Function is good to have but if we not use it properly it will slow down system
- 19. “ ” Let see demo
- 20. REASON To Think
Notas del editor
- Best Practices in database Designing Proper table name, Normalization, Primary key , foreign key etc. Best Practices in SQL writing Reserve word is capital , Joins, Where clause, comment etc. Best Practices in Index creation Index on field, index on field combination etc. Best Practices in Maintenance Full backup, partial backup, Reindex etc.
- What it means ? People just choose the data type not according to business need else they choose according to there own impression. So generally they choose large size for data type field and sometime it works some time not. Why we choose appropriate data type ? Size on the Hard Disk Searching slow in large DB Backup issue (slow)
- What it means ? We forgot to put constraints some time NOT NULL is one of them. If you visit same example if you will find at many places where value. is required according to business but still we allow them null and make the field Null able Why we put constraints ? We thought we will handle all the things in programming but sometime due to some poor programming logic or some misunderstanding we missed such validation and which cause anomalies and data integrity issue.
- What it means ? People are in hurry so they do not write proper joins. You can use Inner Join, Left Outer Join, Right Outer Join, Cross Join etc. It depends on your business condition what to use when. Try to Avoid IN & NOT IN. Why should we avoid IN ,NOT IN? .Performance issue (** Sometime it may not work) How to avoid IN ? How to avoid NOT IN ?
- What it means ? We generally right the query with “*” and sometime we also forgot to write where clause. But as a best practices we should use proper column name if the we have to choose few columns not all. filter data as much as possible don’t think we will do programming and filter there. Why we should use column name, and where clause? less data then on the network it travel fast across network. Programs like ADO.NET /EF keep the data in Memory so if the selection is * with out Where clause it will be in memory. And the application will be slow down later on.
- What it means ? Most of the time people think if a SQL statement execution is slow they not think to much to revise it and try to rewrite it they just apply the Index and there goal is achieved. How & When to Select Index and which index is most suitable ? When you tried your level best in rewriting and there is no other way to fetch fast result then you can apply index at the end. You can create index generally on the fields which are used in WHERE clause, Join.