SQL Server

Char stores a fixed-length string with a maximum length of 8,000 bytes.varchar stores a variable-length string with a maximum length of 8,000 bytes.NCHAR stores a fixed-length Unicode string with a maximum length of 4,000 characters.Nvarchar stores

General countersCollects server performance information for operating system servers, including processor, disk, network, memoryProcessor Processor1.1% Processor time refers to the percentage that the processor uses to perform non-idle threads. This

Empty and set the ID starting value to start at 1.Run statement: TRUNCATE TABLE tablenameDescription: TableName is the name of the data table and changes itself according to the name of the database table you want to empty.Set the ID start value:Run

1. Introduction to CursorsCursors are a method of processing data that is used primarily in stored procedures, triggers, and Transact-SQL scripts. The SELECT statement returns a result set that the cursor can fetch one record at a time from the

To better understand the coverage index, before formally covering the index, let's start by talking a little bit about the basics of indexing.Data pages and index pagesIn SQL Server, the basic unit of data storage is the page, with a page size of

--Create a test tableCreate Table#Temp(seqint Identity, namesvarchar( $))Insert into#Temp(names)Values('Zhang San, John Doe'),('China, USA, Brazil'),('Shenzhen, Shanghai, Beijing, Guangzhou, Harbin'),('football, basketball, table tennis, billiards')

1 usingSystem;2 usingSystem.Collections.Generic;3 usingSystem.Linq;4 usingsystem.web;5 usingSystem.Collections;6 usingSystem.Data.SqlClient;7 8 Public classDatabasehelper9 {Ten Private stringConnectionString =Constants.connectionurl; One A

Original address: http://blog.csdn.net/dba_huangzj/article/details/8309503In recent days, the company's technical maintenance staff frequently let me recover the database, because they are always missing the where condition, resulting in update,

(Refer to self-respecting bird's blog for easy learning and Viewing)1. Request fields on demand, say goodbye to "select *"The extraction of a field must be based on the principle of "how much to use" and avoid using "SELECT *". To do such an

Original: C language connection to SQL Server databaseFirst step: Configure ODBC. There are three ways to configure ODBC with a User DSN, System DSN, and File DSN, and for the sake of security, a System DSN is used.DSN is named LocalServer, account

The number column queried in SQL Server preceded by 0 returns a string of the specified length:Such as:The angle is as follows:/** * * * Script for selecttopnrows command from SSMS * * * **/SELECT TOP +[ ID], [SN], [Name] from [Edudb]. [dbo].

The first two days saw a blog post about how to convert a row of data that contains a single column of multiple values into a multi-row column in Oracle, with the following issues.ID number1 137xxxx,138xxxxTake it out.ID number1 137xxxx1 138xxxxThe

Distinct this keyword is used to filter out redundant duplicate records to keep only one, but it is often used only to return the number of distinct records, rather than using it to return all values that are not re-recorded. The reason is that

Using system;using system.data;using system.data.sqlclient;using system.data.sqltypes;using Microsoft.sqlserver.server;using system.text;using System.Collections.Generic; [Serializable] [Microsoft.SqlServer.Server.SqlUserDefinedAggregate

The SQL Server string is divided into different types, and you will be presented with a few common types of SQL Server strings that you can use to help you learn SQL Server strings.NCharThis data type can store 1~4000 fixed-length Unicode strings,

Original: A brief introduction to snapshots in SQL ServerBrief introductionA database snapshot, as its name implies, is a view of the database at a point in time. is an attribute introduced by SQL Server in the version after 2005. Snapshot scenarios

Function of window functionWindow functions operate on a set of values, do not need to group the data by using the GROUP BY clause, and can also return the columns and aggregate columns of the underlying row in the same row. window functions,

CREATE PROCEDURE Proc_page_withtopmax (@pageIndexint,--Page Index @pageSizeint,--number of displays per page @pageCountintOutput,--total pages, output parameters @totalCountintoutput--total number of articles) asbeginSetnocount on;declare @sql

CREATE Database Data_test on primary (name='Data_test_data', filename='C:\data_test_data.mdf', size=5mb,maxsize=100mb,filegrowth= the%) Log on (name='Data_test_log', filename='C:\data_test_log.ldf', size=2mb,filegrowth=1mb) gouse data_testgocreate

DECLARE @SQLSTR VARCHAR;D eclare my_cursor Cursor--Defines the cursor for (select drop CONSTRAINT' +fk.name+ ' ; ' As Command from sys.foreign_keys FK JOIN sys.all_objects o on fk.parent_ OBJECT_ID=O.OBJECT_ID)--isolate the desired set