When the From List has multiple tables, they must be joined together. What are the various uses of database triggers? Database triggers can be used to enforce business rules, to maintain derived values and perform value-based auditing. What is a event handler in sql?
As part of a series of articles on several data access optimization steps in SQL Server, this article focuses on using indexing to optimize data access.
You have a pretty satisfied client so far as the site was able to attract thousands of users to register and use the site within a small amount of time.
Your client, management, team and you - everybody is happy. Life is not a bed of roses. As the number of users in the site started growing at a rapid rate day by day, problems started occurring. E-mails started to arrive from the client complaining that the site is performing too slowly some of them ware angry mails.
The client claimed that they started losing users. You start investigating the application. Looking into the database, you find that the database tables have grown large in size and some of them were containing hundreds of thousands of rows.
I know why such situations take place, and I can tell you what to do to overcome this. I want to help you do this by sharing my data access optimization experiences and findings with you in this series of articles.
I just hope this might enable you to optimize your data access routines in existing systems, or to develop data access routines in an optimized way in your future projects. But, most of the optimization techniques are roughly the same for other database platforms. Also, the optimization techniques I am going to discuss are applicable for software application developers only.
Database Administrators DBAs also have a great role to play in optimizing and tuning database performance. Let us start our optimization mission in a step-by-step process: Apply proper indexing in the table columns in the database Well, some could argue whether implementing proper indexing should be the first step in the performance optimization process for a database.
But I would prefer applying indexing properly in the database in the first place, because of the following two reasons: This will allow you to achieve the best possible performance in the quickest amount of time in a production system.
Of course, this quick performance improvement can be achieved if you find that indexing is not properly done in the current database. However, if indexing is already done, I would still recommend you to go through this step.
I believe you know what indexing is. So, let us try to understand indexing once again. Let us read a small story. Long ago, there was a big library in an ancient city.
It had thousands of books, but the books ware not arranged in any order in the book shelves. So, each time a person asked for a book to the librarian, the librarian had no way but to check every book to find the required book that the person wanted.
Finding the desired book used to take hours for the librarian, and most of the time, the persons who asked for the book had to wait for a long time.Ampersand (&) operator in a SQL Server WHERE Clause.
Ask Question. up vote 28 down vote favorite. of your queries if used in the predicate. Very easy to manufacture an example of your own. Here is the snippet from my query. Inserting multiple rows in a single SQL query? SQL Server: How to Join to first row. Oct 11, · How do I escape an ampersand in a query executed in the SQL Worksheet in SQL Developer?
For example if my query is: SELECT * FROM EMPLOYEES WHERE status = 'Hired &Fired'; If I execute this query now in SQLD, it asks me to enter a parameter for &Fired, whereas in this case, ampersand is a value in the .
Wonderware® InTouch® HMI Version Service Pack 3 (SP3) Patch 01 Readme. Last revision: 04/29/ About This Readme. This document includes information about Wonderware®InTouch®HMI SP3 (Service Pack 3) Patch Structured Query Language (SQL) is used to perform all database operations, although some Oracle tools and applications simplify or mask its use.
This chapter provides an overview of the issues involved in tuning database operations from the SQL point-of-view. SQL Interview Questions and Answers for Software Developers/Database Developers, Database Administrators and Database Testes. SQL Interview Questions on Subsets of SQL, SQL Data Types, SQL Operators, Data Definition Languages Operations, Data Manipulation Language Operations and Data Control Language Operations.
Standard Connection String Format¶.
This section describes the standard format of the MongoDB connection URI used to connect to a MongoDB database server.