Check whether a table or Column exists in SQL Server

Check whether the table exists

1. Use System View: SYS. Tables

Select name from SYS. tables where name = 'tablaname' and type = 'U'

Type = 'U' is used to exclude stored procedures, views, and system tables. It refers to the user table user_table.

2. Use the System View: sysobjects
Select * From sysobjects where id = object_id ('usersubsyscenthistory _ null') and xtype = 'U'

Xtype = 'U' is used to exclude stored procedures, views, and system tables. It refers to the user table user_table.

Determine whether a Column exists

1. Assume that the table is AAA and the field to be added is the name field.
Select * From syscolumns where [name] = 'name' and objectproperty (ID, 'isusertable') = 1 and object_name (ID) = 'aaa ')

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Note;

Entitymanager em = super. getentitymanager (appconfig. persistence_cent );
Object result = em. createnativequery (SQL). getsingleresult ();

Getsingleresult ()

 

Throws:

NoResultException-If there is no result: the returned value is 0.

NonUniqueResultException-If more than one result: one additional result is returned.

Therefore, ensure that there is only one record. You can use list instead.Getresultlist(), Determine whether there is a result by judging its size.