SQL Server

ObjectiveFinally until this day, I will start to re-system learning database, about the database this piece, no accident, every day will be updated regularly and the content will not contain too much, short content, in-depth understanding, always to

In a database with a large number of transactions, tables and indexes are fragmented over time. Therefore, to improve performance, you should periodically check the fragmentation of tables and indexes, and defragment them with a lot of fragmentation.

First, ExecuteNonQuery and ExecuteScalarUpdates to the data do not need to return a result set, and ExecuteNonQuery is recommended. The network data transfer is omitted because no result set is returned. It simply returns the number of rows affected.

-- =============================================--Author: Wang Wei--Create date:2017-07-06--Description: Synchronize data to attendance schedule when adding, deleting and changing the opening schedule--

Two methods:Original: SELECT (Quantity*Price)/(Quantity*UnitPrice) as [average] from # #表 Error: encountered a divide by zero errors1, in the divisor there to determine whether the denominator is 0 (with 'nullif' function)SELECT

Mysql:Use sakila;--show fields from table_name;--show keys from table_name; SELECT ' referenced_table_name ' from ' information_schema '. ' Key_column_usage ' WHERE ' table_name ' = ' [table_containing _foreign_key] ' and ' column_name ' = '

Mathematical Functions　　1, Calculate absolute value ABSThe ABS function calculates an absolute value (except for the bit data type) for a numeric expression result, which returns an integer.Syntax structure:ABS (numeric expression)Return value: Data

The query slows down when the SQL Server database has been frequently truncated after the data is encountered in the project.I directed the data to another library and found that the query was quick.The underlying reason is that deleting the data

Error symptoms:D:\Program Files\Microsoft SQL Server\mssql.1\mssql\log below Erroelog, hit with text, view run dimension plan unsuccessful is the generated error log details: 2011-08-11 14:16:48-! [298] SQL Server error: 15404, unable to get

Tags: mssql/read-only routingOverviewThe biggest advantage of AlwaysOn relative to database mirroring is the readable copy, which adds a new feature to the read-only route, which is to configure read-only routing to achieve read-write separation; Of

SQL Server system databases are important, and they should not be modified most of the time. The only exception is the model database and the tempdb database. The model database allows deployment changes to any newly created database, such as a

First, the business scenarioWe encountered the need to retrieve subtree data for a parent-child relationship in a real-world production environmentIt is estimated that you have encountered a similar scenario, most typical of which is the provincial

The process of configuring mail for SQL Server 2008 is not written, and there are too many cases on the web.Http://www.cnblogs.com/woodytu/p/5154526.html this case is good.The main write down after the configuration of error handling:Database Mail

One: Create a database:CREATE TABLE INDUSTRIALTOWNTB ([ID] [NVARCHAR] (PRIMARY) KEY not NULL, Industrialnewcityid [NVARCHAR] ($) null, Industrialnewcityname [NVARCHAR] ($) Null,industrialtownid [NVARCHAR] (Null,industrialtownname) [NVARCHAR] (

SQL Server 2000 C# Codesmith Data type Range of values Data type Range of values Null value instead of value Data type bigint -2^63 (-9,223,372,036,854,775,807) to 2^63-1 (9,223,372,

Introduction to Common table expressions:A common table expression (CTE) can be thought of as a temporary result set defined within the execution scope of a single SELECT, INSERT, UPDATE, DELETE, or CREATE VIEW statement. A CTE is similar to a

FileGroup: Filegroups, which are logically divided; files: A file, for the actual file, you need to specify which filegroup the file belongs to.A bit of using multiple files: You can distribute the disk I/O pressure and provide backup by file and

You need to open the Windows Firewall inbound rules on the necessary ports for SQL Server , such as the TCP-1433 port. Special Note: Since the AG is required to use the TCP-5022 port by default, the port must be guaranteed to be open in Windows

First, use the Import data tool:Select data Source: Flat file Source, select a CSV,Advance: Select all Columns (you can choose multiple, use shift),Change outputcolumnwidth:500,Change Datatype:unicode string [DT_WSTR]Second, use the command:　　BULK

Solve the Problem of. net 2014 failure when installing SQL Server 3.5 in Windows 10 Home Edition, 2014.net When installing SQL Server 2014, the. net 3.5 is missing, leading to failure. Later, I studied the following solutions: Update your