Database Component hxj. Data (18) (batch processing)

Batch Processing means that the submitted scripts are not executed immediately, but submitted to a certain number.

Let's start with the example above.

using (DbBatch batch = DbSession.Default.BeginBatchConnection()){    batch.Update<Products>(Products._.ProductName, "apple", Products._.ProductID == 1);    batch.Update<Products>(Products._.ProductName, "pear", Products._.ProductID == 2);    batch.Update<Products>(Products._.ProductName, "orange", Products._.ProductID == 3);}

Generated SQL:

Text: 
UPDATE [Products] SET [ProductName]=@3d40ca14f83644f18269874c99e621a5 
WHERE [Products].[ProductID] = @50999b135fbf4f068f89bda7ab341ac3;
UPDATE [Products] SET [ProductName]=@fe1ea91dd6e14260813ea19abbc245eb 
WHERE [Products].[ProductID] = @6bef4d78041549fa817c3363bd847d41;
UPDATE [Products] SET [ProductName]=@075f1b4639c446be88bfc33638b1f754 
WHERE [Products].[ProductID] = @588a5481ff3d4ff58fc304293173b6ab; 

Parameters: 
@3d40ca14f83644f18269874c99e621a5[String] = apple 
@50999b135fbf4f068f89bda7ab341ac3[Int32] = 1 
@fe1ea91dd6e14260813ea19abbc245eb[String] = pear 
@6bef4d78041549fa817c3363bd847d41[Int32] = 2 
@075f1b4639c446be88bfc33638b1f754[String] = orange 
@588a5481ff3d4ff58fc304293173b6ab[Int32] = 3 

By default, 10 SQL statements are executed once. It can also be customized.

 

DbBatch batch = DbSession.Default.BeginBatchConnection(20)

In this way, 20 SQL statements are executed once.

You can also set the internal transaction level.

Dbbatchbatch = dbsession. Default. beginbatchconnection (20, isolationlevel. readcommitted)

It can also be executed forcibly:

using (DbBatch batch = DbSession.Default.BeginBatchConnection()){    batch.Update<Products>(Products._.ProductName, "apple", Products._.ProductID == 1);    batch.Update<Products>(Products._.ProductName, "pear", Products._.ProductID == 2);    batch.Execute();    batch.Update<Products>(Products._.ProductName, "orange", Products._.ProductID == 3);}

When batch. Execute () is executed, the previous SQL script is submitted first.

Generated SQL:

Text: 
UPDATE [Products] SET [ProductName]=@1ae514d0db3247acb196b8d55110a8e8 
WHERE [Products].[ProductID] = @c694d46594324eec9db0d1e26a3ea499;
UPDATE [Products] SET [ProductName]=@4b1d4e07b6cc45d994e65c5eeac12619 
WHERE [Products].[ProductID] = @58fa8ceaede745f0ac541d5c45574309; 

Parameters: @1ae514d0db3247acb196b8d55110a8e8[String] = apple 
@c694d46594324eec9db0d1e26a3ea499[Int32] = 1 
@4b1d4e07b6cc45d994e65c5eeac12619[String] = pear 
@58fa8ceaede745f0ac541d5c45574309[Int32] = 2 




Text: 
UPDATE [Products] SET [ProductName]=@c3a36b7a94754cd884ee27d4e42199a5 
WHERE [Products].[ProductID] = @550ebc4788f54105ababe5d6bdc9cf2a; 

Parameters: @c3a36b7a94754cd884ee27d4e42199a5[String] = orange 
@550ebc4788f54105ababe5d6bdc9cf2a[Int32] = 3 

The output script is executed twice.

 

Try catch is written as follows:

DbBatch batch = DbSession.Default.BeginBatchConnection();try{    batch.Update<Products>(Products._.ProductName, "apple1", Products._.ProductID == 1);    batch.Update<Products>(Products._.ProductName, "pear1", Products._.ProductID == 2);    batch.Update<Products>(Products._.ProductName, "orange1", Products._.ProductID == 3);}catch{    //do something}finally{    batch.Close();}

The effect is the same as that in the first example.

Batch Processing is also relatively simple.