how to update multiple rows in sql

From: http://www.oecp.cn/hi/zhaolihong/blog/1980 When SQL Server was recently used in projects, it was found that frequent updates and frequent queries cause deadlocks in high concurrency. We usually know that if two transactions insert or modify data to a table at the same time, it will occur when the X lock of the table is requested, and it is already held by the other party. Because the lock is not obtained, the subsequent commit cannot be execute

1. Import table in the same format as the two tables, import data from one table into another table.There are now two records in the Person_old table. Next, insert all the records from the Person_old table into the person table, with the following statement:INSERT into person (id,name,age,info)SELECT Id,name,age,info from Person_old;2. "Modify multiple rows of data"In the person table,

Label:Operations on the database in SQL Server: To delete a table:DROP table NameTo modify a table:ALTER TABLE table name add column Add column list typeALTER TABLE table name drop column name Deleting a databaseDrop database name CRUD OperationsC--create Add data r--read read Data u--update modify data d--delete Delete data 1. Add DataInsert into table name values (' first column value ', ' second column v

operator: The result set used to merge two or more SELECT statements, it is important to note that the SELECT statement inside the Union must have the same number ofColumns, columns must also have similar data types, and the order of the columns in each SELECT statement must be the same.SELECT from User UNION SELECT from The result is: Query the Name field from the user table and the User1 table, respectively, and merge together.It is important to note that the Union operation conforms to t

Tags: applying SQL using the strong set tableThe previous update with a lot of, but are simple single-table operation, no care, recently consulted Multiple Table Association update and update top N, found that the update is really

We will continue to explain the LINQ to SQL statements. In this article, we will discuss the Insert, Update, and Delete operations. This is the most common in our program. Let's look at the example.Insert/Update/Delete operation Insert (Insert) 1. Simple Form Note: A new object is added to the corresponding set using the InsertOnSubmit method and submitted to the

Tags: alert round ble etc provider Operation store Red ZH-CNThe original text uses TOP to limit updated data You can use the TOP clause to limit the number of rows modified in the UPDATE statement. When the TOP (N) clause is used with UPDATE, the delete operation is performed on the randomly selected n rows. For exampl

Q: Please expert advice! The problem is this: I have 1000 data tables, each with the same structure (each table has "QQ,TJ,YJ,EJ,SJ,SIJ,WJ,LJ,ZS,ZJL" 10 fields), but the table name is different. There is also a "Data Update table JJ (TABLE_INDEX,QQ,TJ,YJ,EJ,SJ,SIJ,WJ,LJ,ZS,ZJL)", in addition to the Table_index field, also has "Qq,tj,yj,ej,sj,sij,wj,lj,zs, Zjl "10 fields, 1000 rows, the purpose of which is t

To highlight more important topics in database operations, the following is pinned. Guidelines for updating and deleting data : Do not use the WHERE clause when performing an update or delete, unless you really intend to update or delete each row. Make sure that each table has a primary key, and that it is used whenever possible to use a WHERE clause. Before using an

Today, I wrote a complex SQL statement. The result shows that it does not meet the project requirements, but the syntax is worth learning. Declare @ delid int -- the row to be deleted Declare @ CID int Set @ delid = '000000' Begin transaction T1 Delete from ttest where Unit No. = @ delid Declare mycur cursor for select ID from ttest where convert (INT, unit number)> convert (INT, @ delid) Open mycur Fetch next from mycur into @ CID --

an area using the partial method insertregion provided by DataContext. Calls to SubmitChanges call Insertregion overrides, which use dynamic cud to run the default SQL query generated by LINQ to SQL.Updates (update)Note: The update operation, first gets the object, after the modification operation, directly calls the SubmitChanges () method to commit. Note that

promoted to table-level locks. As a concurrency technique, the use of row versions can also cause ghost record to appear. Ghost Record is not deleted until the transaction is complete. The background thread of SQL Server Ghost-cleanup is responsible for deleting ghost record, but when it is deleted is not expected. The delete operation itself does not inform the GHOST-CLEANUP thread to do so, and subsequent page scans will add a page cont

Tags: SP data bs SQL Information Server nbsp First 500Pre-Preparation:Normal table, temporary table: It has statistical information on the two sessions.Table variable: There is no statistical information.--------------------------------------------------------------------------------------------------------------- -----------------------------------Create a scenario for statistics:1. When you create an index, statistics are created on the appropriate

b.b=a.b);2 into ausing B on (a.b=b.b) when Then Update Set A.C=b.e, a.d=b.f;There are more complicated situations where multiple fields are updated from different tables, such as the D field in table A is derived from a field in the C table, and the individual feels that this situation does not need to be written in a SQL text, div

Step by step vs 2008 +. Net 3.5 (10)-add, query, update, and delete a stored procedure call using dlinq to SQL Author: webabcd IntroductionTaking northwind as the example database, dlinq (LINQ to SQL) calls the ADD, query, update, and delete operations of a specified stored procedure. ExampleRelated stored proceduresAl

The basic algorithm for automatically updating statistics is: · If the table is in the tempdb database table the cardinality is less than 6, automatically updated to the table for each of the six modifications. · If the base of the table is greater than 6, but less than or equal to 500, update the status every 500 of the modifications. · If the cardinality is greater than 500, the table changes when the statistics are updated (tables of 500 + 20%). ·

", sqldbtype.int,4), NewSqlParameter ("@Sex", sqldbtype.int,4)} ;parameters[0]. Value =item. Name; parameters[1]. Value =item. Age; parameters[2]. Value =item. Sex; info. Parameters=parameters; //ParametersstrSQL. ADD (info); //Add multiple SQL statements and execute them together } intnum =Dbhelpersql.executesqltran (strSQL); //execu

When writing SQL scripts, you can use the table alias to greatly reduce the SQLCodeThe table alias is also one of the solutions for multiple references to the same table. You should be familiar with using Table aliases in select: Select * From tablea as a inner join tableb as B on A. key1 = B. key1 However, using the table alias in update may not be known to ma

System.Data.OleDb.OleDbConnection(ConnectionString); cn.Open(); System.Data.DataSet ds = new System.Data.DataSet(); System.Data.OleDb.OleDbDataAdapter da = new System.Data.OleDb.OleDbDataAdapter("SELECT * From a11", cn); System.Data.OleDb.OleDbDataAdapter da1 = new System.Data.OleDb.OleDbDataAdapter("SELECT * From b11", cn); System.Data.OleDb.OleDbCommandBuilder cb = new System.Data.OleDb.OleDbCommandBuilder(da); System.Data.OleDb.OleDbCommandBuilder cb

SQL delete simultaneously deletes records associated with multiple tables Sqlserver supports cascade update and deletion.Oracle only supports cascading Deletion Delete a row that contains the primary key value. This value is referenced by a foreign key column in an existing row of another table. In cascading deletion, all row