Database Administrator

1Prompt NO listening service Solution: Open Net Configuration Assistant and follow the prompts to delete the existing listening service, and then create another one. 2 SQL Plus login prompt user name or password is invalid Cause: Does the

In pinwu performance optimization, Chapter 4.4.3 describes the two features of composite indexes: prefix and optionality. What is prefix? The book explains how to exclude skip scan index (there are not many pre-index columns, such as gender). If the

This note is used to learn constraints, which are everywhere in the table. For example, data in a table cannot be empty or the table id must be set as the primary key. Constraint type: Primary key: The primary key represents a unique identifier in

Zookeeper -- How to view memory consumption of a single process at the OS level AIX: $ Svmon-Pt10 | perl-e 'while (<>) {print if ($. = 2 | $ &&&! $ S ++); $. = 0 if (/^-+ $/)} '---- This shows the top 10 processes that occupy the maximum memory.----

These days, I have been working on big jobs in project management. web programs often encounter this problem, but it will be fine again later. At first I suspected that the session was not closed, but then I checked the code, the main cause is the

SQL Server Stored Procedure Differences between Alter Procedure and Create Procedure: 1. Alter Proc expects to find an existing stored procedure, while Create does not. 2. Alter Proc retains any permissions that have been created in the stored

Basic Concepts 1. Database and database management system 1) a database system consists of databases, hardware, software, and personnel. 2) databases are centrally managed and stored in computers for a long time. They are a collection of organized

1,Sp_helpdb: Reports information about a specified database or all databases.Example: Sp_helpdb -- display all database information (name, size, etc)Example: Sp_helpdb Recruitment -- display Recruitment database information (name, size, etc)2

  I. MongoDB database Introduction IntroductionMongoDB is a high-performance, open-source, non-pattern-based, distributed file storage-based document-type database written in C ++. Its name source is from "hu Mongo"Us" is an open source document

• MongoDB STARTUP configuration 1. startup Item mongod -- help 1.1 Use the config configuration file to start the database and change the port to 8888. Mongodb. conf file Dbpath = D: \ app \ upload data Port = 8888 Start File Mongod.exe -- config

Statistical information is very useful. Without it, the SQL optimizer is like a clever man! A good and efficient SQL Execution Plan depends on real statistics. However, in some cases, for example, to compare the execution plans of the production

Open shell Start mongod -- dbpath d: \ app \ mongodata on the server first. Open shell: mongo localhost: 27017 By default, the test user operation is performed. You can use mongo localhost: 27017/admin to increase the permission. 1. Create a

Connect C ++/C to the MySQL database in Linux (1) I. Preparations before connection Raw Material: Ubuntu12.04LTS (MySQL5.5 or a later version has been installed. The new software package, gcc/g ++ or CodeBlosks compiler) After the above software

When a common table is online redefined as a partitioned table, an error is returned. If the value range exceeds the partition size limit, what steps do I need to redefine the table online? This example records the processing process: SALES @ ORCL>

1. Insert operation The Insert operation is the basic method for MongoDB to Insert data. If you use the Insert operation on the target set, this document is added to MongoDB and the corresponding ID key is automatically generated. The document

CUME_DIST and PERCENT_RANK functions in SQL SERVERCUME_DIST and PERCENT_RANK Functions CUME_DIST: calculates the cumulative distribution of a value in a group of values in SQL Server 2012. That is, CUME_DIST calculates the relative position of a

Temporary table IntroductionMySQL may use temporary tables when executing SQL queries. Generally, using temporary tables means low performance. MySQL temporary tables can be divided into Memory temporary tables and disk temporary tables. Disk

-- This article uses the Oracle database test. The first four queries are a group, and the last two queries are a group. The query in front of each group aims to launch the final query. -- Create a table. to simplify the processing, all field types

A MySQL table is designed in PowerDesigner of Win7. It is only found that MySQL is ready to be imported into the MySQL database.The ODBC program is not installed, and the ODBC configuration is not found in the console. This is too tricky.1. first go

SQL SERVER Data Type The following lists various SQL Server data types:SQL numeric type: Data Type Range Storage Bigint -9,000,000,000,000,000,000To 9,000,000,000,000,000,000 8 bytes Bit 1 or 0 1