Database Query What is the query mechanism used to update data called?

What is a query that updates database table data called a query

Queries that update database table data are called (update) queries.

Update query is a query method used to perform regular batch update and replacement operations on specific data in the data table. If you are familiar with database system tools such as xBase, you can compare it to the update query in Access, which is equivalent to the function of the Replace statement in xBase. Update queries can help us quickly and easily modify the data in the data table to meet specific needs. Whether you are updating a field in a table or replacing data in batches based on conditions, update queries provide a simple and effective way to manipulate data tables.

Data updates can be achieved in two ways: using "Object Explorer" and T-SQL statements. The data update function of SQL language allows DBA or database users to perform data maintenance on the established database.

Extended information:

There is a standard format for database updates: Update table name set field=value where condition. Although it will vary depending on the data source.

1. Input from outside

This is relatively simple

Example: update tb set UserName=＂XXXXX＂ where UserID=＂aasdd＂

2. Some internal variables, functions, etc., such as time, etc.

Assign the function directly to the field

update tb set LastDate=date() where UserID=＂aasdd＂

3. For certain field variables 1, common ones include: click-through rate, number of downloads, etc.

In this way, field 1 is directly assigned to itself

update tb set clickcount=clickcount 1 where ID=xxx

4. Assign one field of the same record to another field

update tb set Lastdate= regdate where XXX

Reference source: Sogou Encyclopedia-Data Update

cUpdate data in the database

SqlConnection conn = new SqlConnection(connStr);

string sql= "update [userInfo] set xc02= @xc02,passWord = @password, ask = @ask WHERE userName= @username";

SqlCommand cmd = new SqlCommand(sql,conn)

sqlParameter[] sqlParas = new sqlPararmeter[]{

new SqlParameter(＂@xc02＂,string xc02),

new SqlParameter(＂@password＂,string password),

new SqlParameter(＂@username＂,string username)

}

foreach(SqlParameter sp in sqlParas)

{

cmd.Parameters.add(sp);

}

conn.open();

cmd.ExecuteNonQuery();

Update database based on excel table

I don’t know what database it is.

I will first assume it is ACCESS, which is the easiest.

In Access, create a link table and link to this Excel file.

The name of this linked table is named A

Assume that the table in your database is B.

So.

UPDATE A INNER JOIN B ON A.C = B.C SET B.D = A.D, B.E = A.E

is to update Excel to the database

UPDATE A INNER JOIN B ON A.C = B.C SET A.D = B.D, A.E = B.E

is to update the database to Excel

For other databases, it depends on whether it supports the function of creating an Excel database link.

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If it is SQL Server, I don’t have SQL 2000 here, only SQL 2008

The following code reports an error here, but I don’t know if it will work in SQL 2000

Execute directly in SQL Server

SELECT *

FROM OpenDataSource(

'Microsoft.Jet.OLEDB.4.0',

'Data Source=＂d:\A.EXCEL＂;User ID=Admin;Password=;Extended properties=Excel 5.0')...[Sheet1$]

or

SELECT *

FROM OpenDataSource(

'Microsoft.Jet.OLEDB.4.0',

'Excel 8.0;DATABASE=d:\A.EXCEL)...[Sheet1$]

Note, replace the Sheet1

above with the name of your Excel sheet and the Sheet with data.

See if it can be retrieved?

If it can be retrieved, updating it is just a matter of SQL statements.

I don’t know if SQL 2000 will report the following error:

SQL Server blocked access to STATEMENT 'OpenRowset/OpenDatasource' for component 'Ad Hoc Distributed Queries' because this component has been closed as part of this server's security configuration. System administrators can enable 'Ad Hoc Distributed Queries' by using sp_configure. For more information about enabling 'Ad HocDistributed Queries', see "Surface Application Configurator"

in SQL Server Books Online

If reported, then use

-- Enable Ad Hoc Distributed Queries:

exec sp_configure 'show advanced options',1

reconfigure

exec sp_configure 'Ad Hoc Distributed Queries',1

reconfigure

-- For safe use, close Ad Hoc Distributed Queries:

exec sp_configure 'Ad Hoc Distributed Queries',0

reconfigure

exec sp_configure 'show advanced options',0

reconfigure

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