删除无名主键语句：
SELECT * FROM USER_CONS_COLUMNS WHERE TABLE_NAME = '表名';
ALTER TABLE 表名 DROP CONSTRAINT 主键名称;
上面语句需要手动，如何自动执行？看下面：
CREATE OR REPLACE FUNCTION DEL_TABLE_CONSTRAINT (tb_name VARCHAR2,
field_name VARCHAR2)
RETURN NUMBER
IS
con_count NUMBER;
con_name VARCHAR2 (32);
BEGIN
con_name := '';
con_count := 0; SELECT COUNT (DISTINCT constraint_name)
INTO con_count
FROM user_cons_columns
WHERE table_name = UPPER (tb_name)
AND column_name = UPPER (field_name)
AND ROWNUM = 1; IF con_count > 0
THEN
SELECT DISTINCT constraint_name
INTO con_name
FROM user_cons_columns
WHERE table_name = UPPER (tb_name)
AND column_name = UPPER (field_name)
AND ROWNUM = 1; EXECUTE IMMEDIATE
'alter table ' || tb_name || ' drop constraint ' || con_name;
END IF; RETURN 0;
END;
这样执行
DECLARE
a NUMBER;
BEGIN
a := DEL_TABLE_CONSTRAINT ('表名', '字段名');
END;
/