There's none, as far as I can tell.
If you have a look at CREATE VIEW script:
CREATE OR REPLACE FORCE VIEW SYS.ALL_CONSTRAINTS ( OWNER, CONSTRAINT_NAME, CONSTRAINT_TYPE, TABLE_NAME, SEARCH_CONDITION, R_OWNER, R_CONSTRAINT_NAME, DELETE_RULE, STATUS, DEFERRABLE, DEFERRED, VALIDATED, GENERATED, BAD, RELY, LAST_CHANGE, INDEX_OWNER, INDEX_NAME, INVALID, VIEW_RELATED ) AS SELECT ou.name, oc.name, DECODE (c.type#, 1, 'C', 2, 'P', 3, 'U', 4, 'R', 5, 'V', 6, 'O', 7, 'C', 8, 'H', 9, 'F', 10, 'F', 11, 'F', 13, 'F', '?'), o.name, c.condition, ru.name, rc.name, DECODE (c.type#, 4, DECODE (c.refact, 1, 'CASCADE', 2, 'SET NULL', 'NO ACTION'), NULL), DECODE (c.type#, 5, 'ENABLED', DECODE (c.enabled, NULL, 'DISABLED', 'ENABLED')), DECODE (BITAND (c.defer, 1), 1, 'DEFERRABLE', 'NOT DEFERRABLE'), DECODE (BITAND (c.defer, 2), 2, 'DEFERRED', 'IMMEDIATE'), DECODE (BITAND (c.defer, 4), 4, 'VALIDATED', 'NOT VALIDATED'), DECODE (BITAND (c.defer, 8), 8, 'GENERATED NAME', 'USER NAME'), DECODE (BITAND (c.defer, 16), 16, 'BAD', NULL), DECODE (BITAND (c.defer, 32), 32, 'RELY', NULL), c.mtime, DECODE (c.type#, 2, ui.name, 3, ui.name, NULL), DECODE (c.type#, 2, oi.name, 3, oi.name, NULL), DECODE (BITAND (c.defer, 256), 256, DECODE (c.type#, 4, CASE WHEN ( BITAND (c.defer, 128) = 128 OR o.status IN (3, 5) OR ro.status IN (3, 5)) THEN 'INVALID' ELSE NULL END, CASE WHEN ( BITAND (c.defer, 128) = 128 OR o.status IN (3, 5)) THEN 'INVALID' ELSE NULL END), NULL), DECODE (BITAND (c.defer, 256), 256, 'DEPEND ON VIEW', NULL) FROM sys.con$ oc, sys.con$ rc, sys."_BASE_USER" ou, sys."_BASE_USER" ru, sys."_CURRENT_EDITION_OBJ" ro, sys."_CURRENT_EDITION_OBJ" o, sys.cdef$ c, sys.obj$ oi, sys.user$ ui WHERE oc.owner# = ou.user# AND oc.con# = c.con# AND c.obj# = o.obj# AND c.type# != 8 AND ( c.type# < 14 OR c.type# > 17) /* don't include supplog cons */ AND (c.type# != 12) /* don't include log group cons */ AND c.rcon# = rc.con#(+) AND c.enabled = oi.obj#(+) AND oi.owner# = ui.user#(+) AND rc.owner# = ru.user#(+) AND c.robj# = ro.obj#(+) AND ( o.owner# = USERENV ('SCHEMAID') OR o.obj# IN (SELECT obj# FROM sys.objauth$ WHERE grantee# IN (SELECT kzsrorol FROM x$kzsro)) OR /* user has system privileges */ EXISTS (SELECT NULL FROM v$enabledprivs WHERE priv_number IN (-45 /* LOCK ANY TABLE */ , -47 /* SELECT ANY TABLE */ , -48 /* INSERT ANY TABLE */ , -49 /* UPDATE ANY TABLE */ , -50 /* DELETE ANY TABLE */ ))); COMMENT ON TABLE SYS.ALL_CONSTRAINTS IS 'Constraint definitions on accessible tables'; COMMENT ON COLUMN SYS.ALL_CONSTRAINTS.CONSTRAINT_TYPE IS 'Type of constraint definition';
you'll see that constraint_type is simply decoded as
DECODE (c.type#, 1, 'C', 2, 'P', 3, 'U', 4, 'R', 5, 'V', 6, 'O', 7, 'C', 8, 'H', 9, 'F', 10, 'F', 11, 'F', 13, 'F', '?'),
If there were a lookup table, it would have probably been used in the FROM clause and joined to other table(s).
