, command to update a table from a single data source, you can perform a merge operation by creating a staging table and then using one of the methods described in this section to update the target table from the staging table.Note You should run the entire merge operation, except for creating and dropping the temporary staging table, in a single transaction so that the transaction will roll back if any step fails.
CREATE TABLE public.dummy ( address_id SERIAL, addr1 character(40), addr2 character(40), city character(25), state character(2), zip character(5), customer boolean, supplier boolean, partner boolean ) WITH ( OIDS=FALSE ); insert into address customer,supplier,partner SELECT case when cust.addr1 is not null then TRUE else FALSE end customer, case when suppl.addr1 is not null then TRUE else FALSE end supplier, case when partn.addr1 is not null then TRUE else FALSE end partner from ( SELECT * from address) pa left outer join cust_original cust on (pa.addr1=cust.addr1 and pa.addr2=cust.addr2 and pa.city=and pa.state=cust.state and substring(cust.zip,1,5) = ) left outer join supp_original suppl on (pa.addr1=suppl.addr1 and pa.addr2=suppl.addr2 and pa.city=and pa.state=suppl.state and = substring(suppl.zip,1,5)) left outer join partner_original partn on (pa.addr1=partn.addr1 and pa.addr2=partn.addr2 and pa.city=and pa.state=partn.state and = substring(partn.zip,1,5) ) where pa.address_id = address_id UPDATE dummy SET customer=subquery.customer, address=subquery.address, partn=subquery.partn FROM (SELECT address_id, customer, address, partn FROM /* big hairy SQL */ ...) AS subquery WHERE dummy.address_id=subquery.address_id; FWIW, Oracle does accept that basic construct, however the performance of the update tends to degrade severely as the tables get larger. though as Oracle also supports the MERGE statement.
For example, you can use the object type to specify the datatype of an attribute, column, variable, bind variable, record field, table element, formal parameter, or function result.
At run time, instances of the object type are created; that is, objects of that type are instantiated. Such objects follow the usual scope and instantiation rules.
Using a single transaction also reduces the number of commits, which saves time and resources.
If you are overwriting all of the columns in the target table, the fastest method for performing a merge is by replacing the existing rows because it scans the target table only once, by using an inner join to delete rows that will be updated.
A collection has only one dimension, but you can model a multidimensional collection by creating a collection whose elements are also collections.