Modifying the SQL Server Table Structure

1. Add Table Fields.

alter table table name add field name type (value) 
 example :alter table tableName add columnName varchar(40);

2. Delete Table Fields.

alter table table name drop column field name 
 example : alter table tableName drop column columnName;

3. Field name renaming.

exec sp_rename 'table name . table name ’ ,'new field name ’
 example :exec sp_rename 'tableName.[columnName]' ,'newColumn';

4. Change field type.

alter table table name alter column field type ;
 example :alter table tableName alter column columnName varchar(50);

5. Table name renaming.

exec sp_rename 'old table name ’ ,'new table name ’
 example :exec sp_rename 'oldTableName' ,'newTableName';

1. Add comments

execute sp_addextendedproperty 
'MS_Description','fill in your field comments',
'user','dbo','table','fill in the form name','column','field name';