oracle PL/SQL 中布尔值的使用
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Use of boolean in PL/SQL
提问by Chandeep
I have a function in PL/SQL which checks if a particular emp_idexists or not which is:
我在 PL/SQL 中有一个函数，它检查一个特定的是否emp_id存在，它是：
CREATE OR REPLACE FUNCTION checkEmpNo(eno numeric)
RETURN boolean IS
emp_number number;
BEGIN
SELECT emp_id INTO emp_number
FROM emp;
IF eno=emp_number
THEN
return true;
ELSE
return false;
END IF;
END checkEmpNo;
The function compiles successfully, but when I try to run it as:
该函数编译成功，但是当我尝试将其运行为：
DECLARE
exist boolean;
BEGIN
exist=checkEmpNo(1);
dbms_output.put_line(exist);
END;
it returns the error:
它返回错误：
ORA-06550: line 5, column 1:
PLS-00306: wrong number or types of arguments in call to 'PUT_LINE'
ORA-06550: line 5, column 1:
PL/SQL: Statement ignored
3. BEGIN
4. exist:=checkEmpNo(1);
5. dbms_output.put_line(exist);
6. END;
EDIT:
编辑：
I also tried this:
我也试过这个：
DECLARE
exist boolean:=true;
BEGIN
if(exist=checkEmpNo(1))
then
dbms_output.put_line('true');
else
dbms_output.put_line('false');
end if;
END;
And it returns the error: ORA-01422: exact fetch returns more than requested number of rows
它返回错误： ORA-01422: exact fetch returns more than requested number of rows
回答by Justin Cave
dbms_output.put_lineis not overloaded to accept a boolean argument. You can do something like
dbms_output.put_line不会重载以接受布尔参数。你可以做类似的事情
dbms_output.put_line( case when exist = true
then 'true'
else 'false'
end );
to convert the boolean into a string that you can then pass to dbms_output.
将布尔值转换为字符串，然后您可以将其传递给dbms_output.
The ORA-01422 error is a completely separate issue. The function checkEmpNoincludes the SELECT INTOstatement
ORA-01422 错误是一个完全独立的问题。该函数checkEmpNo包括SELECT INTO语句
SELECT emp_id
INTO emp_number
FROM emp;
A SELECT INTOwill generate an error if the query returns anything other than 1 row. In this case, if there are multiple rows in the emptable, you'll get an error. My guess is that you would want your function to do something like
SELECT INTO如果查询返回除 1 行以外的任何内容，A将生成错误。在这种情况下，如果emp表中有多行，您将收到错误消息。我的猜测是你希望你的函数做类似的事情
CREATE OR REPLACE FUNCTION checkEmpNo(p_eno number)
RETURN boolean
IS
l_count number;
BEGIN
SELECT count(*)
INTO l_count
FROM emp
WHERE emp_id = p_eno;
IF( l_count = 0 )
THEN
RETURN false;
ELSE
RETURN true;
END IF;
END checkEmpNo;
回答by Rene
Alternatively you can use the Oracle function diutil.bool_to_intto convert a boolean value to an integer: True -> 1, False -> 0.
或者，您可以使用 Oracle 函数diutil.bool_to_int将布尔值转换为整数：True -> 1, False -> 0。
dbms_output.put_line(diutil.bool_to_int(p_your_boolean));
