how to improve query performance

Integrity constraints Integrity constraints are used to enhance data integrity. Oracle provides five integrity constraints: CheckNot nullUniquePrimaryForeign key Integrity constraints are a rule that does not occupy any database space. Integrity

A dba questionNote: You can select and answer the following questions based on your own situation. You do not have to answer all the questions. You can also directly contact the interviewer to answer the questions without answering them. I. SQL

Cloud computing Design Model (14)--manifested view modeWhen a pre-populated view of data in one or more data stores is generated, the data is formatted in a way that is detrimental to the desired query operation. This pattern can help support

Through the previous two articles we basically learned how to combine the execution plan to analyze the performance of a SQL statement, since there is a performance problem has been found, the next is how to optimize the query to improve query

Original: SSAS Series--"03" Multidimensional data (Cube object)1. What is cube?A simple Cube object consists of basic information, dimensions, and measure groups. Basic information includes the name of the cube, the default measure for the cube, the

Objective The previous sections are all about the basics, and we'll talk about index performance optimization in this section, when the large data processing first thought is the index, once encountered such a problem is a rush, all kinds of

As data volumes grow at an alarming rate, the database management system continues to focus on performance issues. This paper mainly introduces a performance tuning technique named function index (functional index). Creating and using functional

server| View | index | performance What is an indexed view? For many years, Microsoft®sql Server™ has been providing the ability to create virtual tables, called views. In the past, these views have two main uses: Provides a security mechanism for

I. Indexed views For years, MicrosoftSQL Server has supported the creation of virtual tables called views. Typically, the main functions of these views are: Provides a security mechanism that restricts users to a dataset in one or more base tables.

2014-08-22 BaoxinjianI. Summary 1. Partition table:As the table continues to grow, it is more difficult to maintain the new record's increase, find, delete, and so on (DML). For a very large table in a database, you can simplify the management

Brief introduction With the increasing application of DB2, more and more database developers are confronted with the problem that the query is too complicated and the performance is difficult to be accepted in the process of project development.

Original addressPick up an articleModel tree structure of parent Reference Model tree structureThis data model describes a tree structure that stores references to parent nodes in child nodes.ModeThe parent reference mode stores each tree node in

2014-10-13 15:04:34goal : Support scalability. Optimize the structure of the database to improve query performance and support smooth scaling of tables.anti-pattern : Clone table and Clone column1. Split a very long table into multiple smaller

ObjectiveIn the previous article we analyzed the role of statistical information in the database, and we have learned how the database uses statistics to control the distribution of the contents of tables in the database. Children's shoes are not

ObjectiveIn the previous article we analyzed the role of statistical information in the database, and we have learned how the database uses statistics to control the distribution of the contents of tables in the database. Children's shoes are not

There are many articles about nolock in the blog Park, most of which are well written, for example: http://www.cnblogs.com/huangxincheng/p/4292320.htmlThis is a personal note that only combines individual items.Nolock methods of use such as:SELECT *

A new feature to enhance non-clustered indexes, filterindex, was introduced from 2008. You can use statements with where conditions to create non-clustered indexes, filters out unnecessary data, reduces index maintenance overhead and storage space,

I. SQL tuning class 1: List several table Connection MethodsHash join/merge join/nest loop (cluster join)/index join 2: How to view SQL Execution plans without using third-party toolsSet autot onExplain plan set statement_id = & item_id for &

1. materialized view Overview The Materialized View of Oracle is a database image that contains a query result. It is a local copy of remote data or is used to generate a summary table based on the sum of data tables. Materialized View stores data

Mu class network decryption PHP fuzzy Query technology Learning notes!For the previous knowledge of the consolidation, you can jump-type selective viewing!/*** Decryption PHP Fuzzy query technology** This lesson is the introduction of PHP Fuzzy