CREATE TABLE test_table
( somecol  VARCHAR2(30)
           CONSTRAINT somecol_no_numeric_chars_chk
                      CHECK (somecol = TRANSLATE(somecol,'1234567890','£')) );

SQL> CREATE TABLE Test
  2    (COL VARCHAR2(20) CHECK (NOT REGEXP_LIKE(COL, '[[:digit:]]')));

Table created.

SQL> INSERT INTO test (col) VALUES ('abcd');

1 row created.

SQL> INSERT INTO test (col) VALUES ('abcd1234');
INSERT INTO test (col) VALUES ('abcd1234')
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.SYS_C0016148) violated


SQL> INSERT INTO test (col) VALUES ('1122abcd');
INSERT INTO test (col) VALUES ('1122abcd')
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.SYS_C0016148) violated


SQL> INSERT INTO test (col) VALUES ('12345');
INSERT INTO test (col) VALUES ('12345')
*
ERROR at line 1:
ORA-02290: check constraint (SCOTT.SYS_C0016148) violated