Performance Optimization 3--Database optimization

Source: Internet
Author: User
Tags sqlite

1> Index

Although the purpose of the index is to improve the performance of the database, there are several situations where you need to avoid using indexes. The following guidelines should be reconsidered when working with indexes:

The index should not be used on smaller tables. Indexes should not be used on tables that have frequent bulk updates or insert operations. The index should not be used on columns that contain a large number of NULL values. Indexes should not be used on columns that are frequently manipulated.

2> transactions

  For a transaction, it is an atomic execution of the database. Atomic execution provides reliable security for the integrity of the data. In SQLite, if our default transaction (which creates a transaction for each insert and update, and commits the operation immediately after each insert and update), i.e. no transaction is created manually, assuming there are 1000 data at this time, then the execution of the data is to create the transaction, perform the INSERT or update operation- > commits the transaction, so the process executes 1000 times. If we created the transaction manually, the execution process is: Create transaction, execute 1000 SQL data operations, COMMIT transaction. Obviously, the use of transactions in SQLite can lead to great optimizations for insert and update operations. Here's how to use transactions in SQLite:

From what we see, the execution of a transaction is divided into four steps: Start transaction, execute SQL, set transaction execution success, end transaction

Performance Optimization 3--Database optimization

Contact Us

The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion; products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the content of the page makes you feel confusing, please write us an email, we will handle the problem within 5 days after receiving your email.

If you find any instances of plagiarism from the community, please send an email to: info-contact@alibabacloud.com and provide relevant evidence. A staff member will contact you within 5 working days.

A Free Trial That Lets You Build Big!

Start building with 50+ products and up to 12 months usage for Elastic Compute Service

  • Sales Support

    1 on 1 presale consultation

  • After-Sales Support

    24/7 Technical Support 6 Free Tickets per Quarter Faster Response

  • Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.