Tag：sqlserver
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Time：2021-1-31
Trigger is a method provided by SQL server to programmers and data analysts to ensure data integrity. It is a special stored procedure related to table events. Its execution is not called by program or started manually, but triggered by events. For example, when a table is operated (insert, delete, update), its execution will be […]
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Time：2021-1-24
In fact, there are only two decimal value types in SQL server, namely, float (approximate value) and decimal (exact value). These two types can represent all decimal value types. Float (approximate numeric type) Float represents the approximate value, and there is a certain lack of accuracy. float(n) Here n is the number of bits of […]
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Time：2021-1-11
preface SQL server uses try… Catch structure to implement TSQL statement error handling. Try command is responsible for monitoring the execution of the statement. If there is an exception in TSQL statement, and the severity level is greater than 10 and less than 20, then catch command will catch the exception error. BEGIN TRY { […]
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Time：2021-1-4
1、 SQL Server row_ Introduction to number function ROW_ Number () is a window function that assigns a continuous integer to each row in the partition of the result set. The line number begins with the line number of the first line in each partition. Here is row_ Syntax example of number() function: select *，row_number() […]
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Time：2020-12-31
The requirement is to use SQL server to generate a series of continuous numbers according to the specified number and table, which is similar to the function of rownum in Oracle 1、 Implementation of Oracle using rownum SELECT ROWNUM number_list From table name WHERE ROWNUM <= 10; 2、 There are three ways for SQL server […]
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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 […]
