SQL Server

(1)Char, varchar, text, nchar, nvarchar, ntextChar and varchar are both between 1 and 8000 characters in length. The difference is that char is a fixed-length character data while varchar is a variable-length character data. The so-called fixed

During this time, the project needs to import the original data to the new database, and the duplicate data needs to be deleted. I use the cursor method to solve this problem. The SQL statement is as follows to avoid forgetting. Code Code

Protected void button#click (Object sender, eventargs E){String sqlconn = system. Web. configuration. webconfigurationmanager. connectionstrings ["sqlconn"]. connectionstring; String mystring = "provider = Microsoft. Jet. oledb.4.0; Data Source = E:

ConvertExplicitly converts a data type expression to another data type. Because some requirements often use different date formats, the following can be found inFormat the date in SQL Server. SQL Server supports the use of KuwaitAlgorithmData

{******************************** Copyright jack_0424@126.com 2006, 4, 16 Function Description:Back up SQL Server database files to a Local Machine Implementation ideas:Because the backup files of SQL Server can only be stored on the machine

(1) The master database is the most important database in the SQL server system. It records all system information of the SQL server system. The system information includes all logon information, system settings, SQL Server initialization

Scenario: A User table and an order table are required to obtain the latest order information for a user. To meet the above requirements, we can use the following methods, but the efficiency is quite different. First, create an index in the

Char (or nchar) and varchar (or nvarchar) are the most common data types used to store character data in databases. Because they have the same majority of features, when selecting which type of character data to use, There may be some questions.

When defining a column's data type decimal in SQL Server, you must specify its precision and number of decimal places. Precision: the total number of digits in the decimal place, including the digits on the left and right of the decimal point. The

As we all know, adds, deletes, and modifies data first in the memory, which can greatly speed up data operations. When the data in the memory is modified, and the data in the disk is Before modification, a so-called "dirty page" is generated. How

SQL ServerDatabaseObtain the content length of the text field.What about it? This article introduces SQLThe server database obtains the content length of the text field throughDatalengthFunction. Next we will use the syntax of the datalength

1. Select the first n rows of data You can use top in SQL Server to specify the returned rows. It is important for the top and with ties options. It can append multiple rows to the result set returned by top. These rows have the same value as the

In the SQL Server 2005 SP3 environment, we found the following strange phenomenon when we accidentally used between to query date data: paymentdate is smalldatetime 23:59:59 is still outside 0:00:00? Continue to try and find that the time is

Index instructions Digress: Yesterday, we were depressed. When we maintained a customer's database system, we found that the system was processing data and there was a false death. At first, Because of software problems, I was too busy to copy

Database optimization considerations: 1. Create an index for the key fields. 2. Using Stored Procedures makes SQL more flexible and efficient. 3. Back up the database and clear junk data. 4. SQL statement syntax optimization. (You can use

I develop C # winform myself. Recently came into contact with a task. Generate a script to create the table based on an existing table in SQL. First, we want to solve the problem from the perspective of stored procedures. I read some documents

This article is from the 51cto blog (cannot stop V) Varchar uses a single byte to store data in SQL Server. nvarchar uses Unico to store data. when a Chinese character is stored in SQL Server, it is saved as two bytes (generally Unico encoding),

I have not solved this problem. When a netizen asks me this question,I thought it was quite simple.,Assume that SQL Server should provide corresponding system variables or something.But so far,I have not yet obtained a better solution. It may

A few days ago, I read the article in the SQL section of SCID and explained how to quickly delete duplicate records in SQL Server. I browsed it. The author used four methods: creating temporary tables, using cursors, and using unique indexes. After

PHP php_mssql.dll files cannot meet the requirements of SQL server2005 and later versions. Microsoft also released the SQL Server Driver for PHP for corresponding support. SQL Server Driver for PHP supports different php versions. 1. SQL Server