Data | database | Index just like many PHP developers, I used relatively simple data structures when I first started building dynamic websites. PHP is really very convenient to connect to the database (translator Note: Some people think that PHP is
E-commerce This paper demonstrates the application of PHP and Postgressql in e-commerce through a simple Web application.
Not long ago, if a serious web application was to be structured, it meant buying expensive cold Fusion licenses and a
--Data manipulation
SELECT-Retrieve rows and columns of data from a database table
INSERT-Add new data rows to a database table
Delete-Deletes rows of data from a database table
Update--updating data in a database table
--Data definition
The server transaction log (Transaction logs) is a very important but often overlooked part of the database structure. Because it is not as active as the schema in the database, few people are concerned about the transaction log.
The transaction log
Introduced:
For 10GR2, it can be divided into several categories:
Range (range) partition
Hash (hash) partition
List (lists) partition
and combined partitions: Range-hash,range-list.
Preparation environment:
--1, building three table spaces
One of the pitfalls of indexing using indexes: Leading columns that do not use a composite index cause the query to not use the index
In Oracle, we often assume that indexed, SQL queries use the index as we would like, in fact, Oracle only uses
Oracle-CREATE TABLE (creating a partition Table)
CREATE TABLE Bill_monthfee_zero
(
SERV_ID number is not NULL,
Billing_cycle_month Number (6) is not NULL,
Date_type number (1),
ACC_NBR VARCHAR2 (80)
)
Partition by range
These days to learn about the MySQL database on the nature of the optimization and design content, now do a summary of their own learning, follow-up I will continue to study further, improve the following summary:
1. Use index
Up to 16 indexes per
Solution | data | database | problem | performance | optimization | statement
Problem Description:
October 25 Morning Binzhou Netcom's Engineers report OSS application system running slowly, the specific operation is through the OSS system query, a
Server IP Address 192.168.1.25
Lampàlinux +apache +mysql +php
1. Install Apache Service
[Root@localhost ~]# Yum Install Httpd–y
2. Install MySQL Service
[Root@localhost ~]# yum list all |grep MySQL
[root@localhost ~]# yum install MySQL
SQL syntax
BETWEEN ... And operator
Determines whether a person's numeric value is within a specific range, and this operator can only be used in SQL statements.
Expr[not]between value1 and value2
Expr
Specifies the combination of fields and
Method 1: Define the appropriate referential integrity constraints between the fact table and the three dimension tables
In DB2, you can define primary key and foreign key constraints to allow the database manager to enforce referential integrity
MySQL Display database or table:
Show databases;//can then use database_name;
Show tables;
MySQL Change table name:
ALTER TABLE table_name rename new_t;
MySQL Add columns:
ALTER TABLE table_name ADD column c_n column attributes;
MySQL Delete
Data | database
Overview of the SQLJ
Today's enterprise-class applications typically run on multiple database platforms, such as Oracle, DB2, Sybase, SQL Server, Informix, and so on. In this environment, the migration and maintainability of code is
9i Online redefinition There is a problem, after the completion of online redefinition, the table's name, although the same, but the index, constraints, triggers and other associated objects will change the name, sometimes this will bring some
The Oracle Digital dictionary contains a little-known v$session_longops view. The V$session_longops view enables Oracle experts to reduce the elapsed time of a long-running DDL and DML statement.
For example, in a data warehouse environment, even
The parameter Optimizer_index_cost_adj sets the cost-consumption relationship between the index scan and the full table scan, with a default value of 100, which means that Oracle calculates the query cost at the same cost as the index lookup and
I've often seen people ask this question, I've set up multiple indexes on the same table, why does Oracle choose one at a time and not use multiple indexes at the same time? Generally speaking, the common access to the same table more than two
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