Oracle – Reset Sequence in oracle 11g

SELECT owner, table_name
  FROM dba_tables

This is assuming that you have access to the DBA_TABLES data dictionary view. If you do not have those privileges but need them, you can request that the DBA explicitly grants you privileges on that table, or, that the DBA grants you the SELECT ANY DICTIONARY privilege or the SELECT_CATALOG_ROLE role (either of which would allow you to query any data dictionary table). Of course, you may want to exclude certain schemas like SYS and SYSTEM which have large numbers of Oracle tables that you probably don't care about.

Alternatively, if you do not have access to DBA_TABLES, you can see all the tables that your account has access to through the ALL_TABLES view:

SELECT owner, table_name
  FROM all_tables

Although, that may be a subset of the tables available in the database (ALL_TABLES shows you the information for all the tables that your user has been granted access to).

If you are only concerned with the tables that you own, not those that you have access to, you could use USER_TABLES:

SELECT table_name
  FROM user_tables

Since USER_TABLES only has information about the tables that you own, it does not have an OWNER column – the owner, by definition, is you.

Oracle also has a number of legacy data dictionary views-- TAB, DICT, TABS, and CAT for example-- that could be used. In general, I would not suggest using these legacy views unless you absolutely need to backport your scripts to Oracle 6. Oracle has not changed these views in a long time so they often have problems with newer types of objects. For example, the TAB and CAT views both show information about tables that are in the user's recycle bin while the [DBA|ALL|USER]_TABLES views all filter those out. CAT also shows information about materialized view logs with a TABLE_TYPE of "TABLE" which is unlikely to be what you really want. DICT combines tables and synonyms and doesn't tell you who owns the object.

During compile time sequence not exists so compiler returns error. Execute immediate will be executed on runtime but compiler don't know that it will create sequence you called later in code.

create or replace procedure createtest as
begin 
execute immediate 'create table t1 (c1 number)';
insert into t1 values (1);
end;
/

Gives the same error as yours as table t1 not exists. So insert statement is invalid. This is error during compilation of PL/SQL.

create table t1 (c1 number);

After that I can create procedure but when I do:

exec createtest;

I got error that table already exists. But compiler didn't knew that I'm trying create again same table so it will be returned on run not during compilation.

If you really need to do it such way please do:

create or replace procedure createtest as
begin 
execute immediate 'create table t1 (c1 number)';
execute immediate 'insert into t1 values (1)';
end;
/

In you case:

execute immediate 'SELECT emp_seq.nextval FROM dual' INTO empid;

[EDIT] What I understand is you want to be sure that sequence is set to max(empid) so please do not try to create it inside procedure. Create sequence once then in procedure body execute:

select max(empid) into maxempid from employee;
select emp_seq.currval into maxseq from dual;
if(empid-maxseq>0) then
execute immediate 'alter sequence emp_seq increment by ' || empid-maxseq;
end if;