CREATE TABLE project
(
   pid   VARCHAR2 (50)
            CONSTRAINT ch_pid_format CHECK (REGEXP_LIKE (pid, '^PID[0-9]+$'))
);

alter table project
  add constraint project_chk1
    check(
              pid like 'PRJ_%'
          and
              rtrim(pid,'0123456789') = 'PRJ'
         )
/

alter table project
  add constraint project_chk1
    check(
          translate(pid,'0123456789','0000000000') = 'PRJ0000'
         )
/

alter table project
  add constraint project_chk1
    check(
          translate(pid,'0123456789','0000000000') = 'PRJ000000'
         )
/

SQL> drop table tbl purge
  2  /

Table dropped.

SQL> create table tbl(pid varchar2(9))
  2  /

Table created.

SQL> alter table tbl
  2    add constraint tbl_chk1
  3      check(
  4            translate(pid,'0123456789','0000000000') = 'PRJ000000'
  5           )
  6  /

Table altered.

SQL> set timing on
SQL> insert
  2    into tbl
  3    select 'PRJ' || lpad(level,6,'0')
  4      from  dual
  5      connect by level <= 10000
  6  /

10000 rows created.

Elapsed: 00:00:00.02
SQL> set timing off
SQL> drop table tbl purge
  2  /

Table dropped.

SQL> create table tbl(pid varchar2(9))
  2  /

Table created.

SQL> alter table tbl
  2    add constraint tbl_chk1
  3      check(
  4            regexp_like(pid,'^PRJ\d{6}$')
  5           )
  6  /

Table altered.

SQL> set timing on
SQL> insert
  2    into tbl
  3    select 'PRJ' || lpad(level,6,'0')
  4      from  dual
  5      connect by level <= 10000
  6  /

10000 rows created.

Elapsed: 00:00:00.04
SQL> set timing off
SQL>