Tag：sqlserver
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Time：2020-11-27
1. Select the most efficient table name order (only valid in rule-based optimizer) The parser of SQL server processes the table names in the from clause in the order from right to left. Therefore, the last table (driving table) written in the from clause will be processed first. If there are multiple tables in the […]
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Time：2020-11-1
Trigger is a special type of stored procedure, which is different from the stored procedure we introduced before. Triggers are triggered by events and are automatically called and executed. A stored procedure can be called by its name. What is a trigger A special stored procedure that is automatically executed when a trigger inserts, updates, […]
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Time：2020-10-27
The scope of application of this paper: a comprehensive description of SQL Server database operations, divided into virtual host and server two cases. This is a long article. Please use the outline below to access it. outline 1、 Virtual host Enterprise manager online installation2. Register remote enterprise manager (SQL2000)3. Register remote enterprise manager (SQL2005 / […]
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Time：2020-10-12
preface If you have just used the Entity Framework core as the ORM framework, you will surely encounter some problems with database migration. At first I was in ASP.NET It was carried out in the web project of core, but later it was found that it was not very reasonable to put it here. Some […]
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Time：2020-10-7
preface The project is generally divided into test environment (QAS) and production environment (PRD). When our project has experienced a long period of update, when we publish to the production environment, the first task is to update the new tables and fields to the production database. Many times, when we release updates, it’s hard to […]
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Time：2020-10-5
preface In the SQL Server database, sometimes some windows authentication accounts (domain accounts) will be established. For example, our company is used to opening NT account permissions to developers and support colleagues. If there is resignation or change of responsibility, how to correctly delete these windows authentication accounts? This article is to explore how to […]
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Time：2020-9-27
Now I have two tables, S_ PERSON,S_ USER S_PERSON S_USER I want to put the s_ Modify account in user table to s in batch_ Account of person We can find s_ There is an s in the user table_ The field associated with the person table is person_ ID, which is also the condition […]
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Time：2020-9-26
Environment: one SQL Server 2008 R2, one web serverSoftware support: IIS, dynamic website source codeTopology: Steps: Database part: 1. Start – click SQL Server Management Studio 2. Enter the name or IP address, login name and password of SQL server server – click link database 3. Create a new database 4. Enter new database name […]
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Time：2020-9-26
SQL statements can specify aliases for table or column names. (aliases are sometimes referred to as export columns. Whether they are export columns or aliases, they represent the same thing.) SQL aliasSQL aliases are used to provide temporary names for tables or columns in tables. SQL aliases are often used to make table or column […]
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Time：2020-9-22
Declare usage in SQL I usually write SQL queries and stored procedures by feeling. I haven’t explored the specific syntax of SQL. I always imitate SQL according to C ා. A problem encountered in the project a few days ago has aroused my interest in the scope of declare defined variables. We all know the […]
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Time：2020-9-22
1 Overview Generally speaking, three principles should be followed in database design, that is, the three paradigms we usually refer to. The first paradigm requires to ensure the atomicity of each column in the table, that is, it can not be split; the second paradigm requires that each column in the table is related to […]
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Time：2020-9-21
Q1: the student scores table is as follows. Use an SQL statement to query the names of students whose scores are greater than 80 in each course Q2: table demo_ Delte is as follows: delete all the same student redundant information except for different automatic numbering Q3: the team table is as follows: A, B, […]
