Oracle 11g prompts a solution for "ORA-01788: require connect by clause in this query block" when creating a remote materialized view

A solution that prompts "ORA-01788: This query block requires a connect by clause" when creating a remote materialized view on Oracle 11g maps a table on the remote server to a local materialized view, use the following statement: www.2cto.com ---- create database link lnk connect to user1 identified by pwd1 using '(DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP) (Host = 172.17.211.114) (PORT = 1521) (CONNECT_DATA = (SERVER = DEDICATED) (SID = REMOTEDB) '; -- create a materialized view, update automatically every two days; CREATE MATERIALIZED VIEW DEPARTMENT R Efresh force start with sysdate next sysdate + 2 with primary key as select * FROM user1.DEPARTMENT @ lnk WHERE 1 = 1; Result: "ORA-01788: the connect by clause is required in this query block ". Google cannot be accessed. Baidu search is too boring. Bing is used to get clues. Solution: execute the following statement in the local database: alter system set "_ ALLOW_LEVEL_WITHOUT_CONNECT_BY" = true scope = both OK! Source http://www.cnblogs.com/downmoon/archive/2012/12/14/2817939.html