Gbase 8C mode visibility query function (I)

Each function executes to check the visibility of the database object type . For functions and operators , If there is no data type with the same object name and parameters in the previous search path , Then this object is visible . For operator classes , Then we should consider the access methods of names and related indexes at the same time .

All these functions need to use OID To identify the object to be checked . If the user wants to test the object by name , Then use OID Alias type （regclass、regtype、regprocedure、regoperator、regconfig or regdictionary） It will be very convenient .

such as , If the schema of a table is in the search path , And there is no table with the same name in the previous search path , Then this table is visible . It is equivalent to a table that can be referenced without explicit schema decoration . such as , To list the names of all visible tables ：

 gbase=# SELECT relname FROM pg_class WHERE pg_table_is_visible(oid);

                    relname

------------------------------------------------

 pg_type

 gs_client_global_keys_args

 abc

 pg_subscription_oid_index

 pg_subscription_subname_index

 pgxc_prepared_xacts

 pg_shadow

 pg_roles

 pg_user

 pg_group

 pg_rules

 pg_authid

 gs_labels

 pg_rlspolicies

 gs_auditing_access

……