Extract created and last modified data
От | Gordon McVey |
---|---|
Тема | Extract created and last modified data |
Дата | |
Msg-id | AANLkTi=W7vwAFxKEkFMHvm-hteNCBi1eJ5vYJA2qWDn0@mail.gmail.com обсуждение исходный текст |
Список | pgsql-sql |
I have a CMS with a table of items, and another table serving as a log <br /> of operations performed on the items. Therevelent table structure is <br /> as follows: <br /><p>items <br /> itm_id | usr_id_create | itm_date_create | usr_id_modify| <br /> itm_date_modify | ..... <br /><p>itm_id is a serial primary key. <br /><p>usr_id_* are the keys ofthe users who created and last modified the <br /> item. <br /><p>item_date_* are timestamps for creation and last modificationtimes. <br /><p>changelog <br /> itm_id | usr_id | log_timestamp | log_op <br /><p>itm_id and usr_id are foreignkeys into the respective item and user <br /> tables. log_timestamp is when the last change was made and log_op was<br /> the operation performed. <br /><p>I realised that the creation and last modified data was being stored <br /> intwo places, and this is causing some issues with desynching. I'm <br /> thinking of removing the creation and last modifiedfields from the <br /> items table and using a view to fetch the create data and ID, and the <br /> last modifieddate and ID from the changelog table instead. However <br /> I'm not sure of how to do this, and how it would impactperformance. <br /><p>Can anybody help with writing the query to get a view that replicates <br /> the items tableexcept with the create and last modified user IDs and <br /> timestamps loaded from the changelog table? If there isanybody who <br /> has actually implemented something similar, what kind of performance <br /> impact would it have? <br/>
В списке pgsql-sql по дате отправления: