create index

Oracle's online segment contraction (on-line Segment Shrink) refers to the online defragmentation of fragments in the space, which has the following characteristics: Online, that is, DML is almost unaffected during segment compression (only a short

"No rules, RADIUS," the code layout of the canonical database script file has the following important meanings: (1) The code can display a good logical structure, improve the accuracy, continuity, readability and maintainability of the code. (2)

Objective: This paper describes a TENS data retrieval (search engine) architecture which has been tested by production environment. This article only lists the content excerpts from the previous chapters and does not provide full text content. On

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

oracle| Performance | optimization 43. Where to replace the order by The ORDER BY clause uses the index only under two strict conditions. All columns in the order by must be contained in the same index and remain in the index. All columns in

1. sh File contents The file name in this article is example.sh, which reads as follows: #!/bin/bash function Init () { If [-F "Example.sql"] Then echo "Example.sql is exits and is deleting it,then recreate it" Rm-fexample.sql Else echo

The partition key value of the list partition table is a discrete value, so it has DDL maintenance statements that are unique to other partitions, ADD values, and Dorp values. Add values and drop values increase or decrease the corresponding

This paper mainly describes how to accelerate the Dynamic Web site MySQL index analysis and optimization. One, what is an index? Indexes are used to quickly look for records with a specific value, and all MySQL indexes are saved as a B-tree.

I. Data definition DDL (data definition Language) Data-setting language refers to the language defined in the format and form of data, he is the first to be set up when each database is to be established, what is the form of data, the form of a

In the process of using Oracle, we often encounter some Oracle errors, for beginners, these errors may be a little fuzzy, and may not know how to deal with these errors, I used to appear in the more frequent error code one by one to make analysis,

Oracle second part, Oracle Architecture system [Q] Oracle has those data types [A] common types of data are Char fixed length character value field, maximum length up to 2000 bytes NCHAR a fixed-length character value field of a multibyte character

Over the past decade, Oracle has become one of the most professional databases in the world. For IT professionals, it is important to ensure that Oracle's powerful features are used to improve the productivity of their companies. One of the most

One, the importance of indexing Indexes are used to quickly find rows that have a specific value in a column. Without indexing, MySQL must start with the 1th record and read through the entire table until the relevant rows are found. The larger the

First, the preface See a document about SQL Server table partitioning on MSDN: Special guidelines for partitioned indexes, it's harder to understand the meaning of a document if you don't have actual experience with the table partition. Here I will

access| Tips | Statement where you should pay attention to using SQL statements in Access and some tips Quote: Fred The following SQL statement tests through the query in Access XP Build table: Create Table TAB1 ( ID Counter, Name String, Age

Data | database | Index Then, a little bit more complicated, what if there is an ORDER BY clause? Believe it or not, most databases will benefit from the index when they use the order by. SELECT * FROM MyTable WHERE category_id=1 and

Data | database SQLite is a lightweight database, its design goal is embedded, and has been used in many embedded products, it occupies very low resources, in embedded devices, may only need hundreds of K of memory is enough. It can support

SQLite is a lightweight database system similar to access, but smaller, faster, more capacity, and more concurrent. Why is SQLite most suitable for CMS (Content management system)? Not that other databases are bad, Oracle, MySQL, SQL Server are also

/**** query Builder translated by PHP siege Http://blog.csdn.net/phpgcs preparing query Builder preparation Qu ery Builder Building Data retrieval Queries build up a search query building and data manipulation Queries to build a database operation

Part I: Profile concept Oracle database 10g uses a new approach called SQL configuration files to compensate for the drawbacks of storage profiles, DBAs can use SQL Tuning Advisor (STA) or SQL Access Advisor (SAA) to identify SQL statements that