如何创建 ORACLE 序列以根据另一个 table 填充维度 Table

Question

编辑：为了清楚起见，我修改了我原来的问题。希望这有助于更清楚地解释我要完成的工作。

我有一个标准的 SQL table VEHICLES，我用 RENAME 语句将其名称更改为 OLTP_VEHICLES。

我创建了一个新的 VEHICLES table 作为维度 table，它是我的数据库星型模式的 "beginning"。

我现在需要完成以下任务：

"For the vehicleCode primary key column, use an Oracle Sequence to populate the values. For the vehicleDescription column, use a concatenated combination of vehicleMake and vehicleModel from the OLTP_VEHICLES table."

我需要通过使用 PL/SQL 块来完成此操作，通过从 OLTP_VEHICLES table 中选择 vehicleMake 和 vehicleModel 来填充描述列然后通过循环中的游标将串联组合插入 VEHICLES 维度 table。

看到这条指令，我完全莫名其妙。我认为我之前让你们这些好人感到困惑的地方是我遗漏了涉及插入 vehicleMake 和 vehicleModel 连接的 "second part"。

这是否有助于更好地解释我所追求的？如果没有，我深感抱歉。我对此很困惑，甚至无法解释它。再次感谢您的帮助。

CREATE TABLE VEHICLES
(vehicleVIN     VARCHAR(25) PRIMARY KEY,
vehicleType     VARCHAR(10) NOT NULL CHECK (lower(vehicleType) IN ('compact', 'midsize', 'fullsize', 'suv', 'truck')),
vehicleMake     VARCHAR(15) NOT NULL,
vehicleModel        VARCHAR(15) NOT NULL,
vehicleWhereFrom    VARCHAR(20) NOT NULL CHECK (lower(vehicleWhereFrom) IN ('maryland','virginia','washington, d.c.')),
vehicleWholesaleCost    DECIMAL(9,2)    NOT NULL,
vehicleTradeID      INT);

INSERT INTO VEHICLES
(vehicleVIN,vehicleType,vehicleMake,vehicleModel,vehicleWhereFrom,vehicleWholesaleCost,vehicleTradeID)
VALUES
('147258HHE91K3RT','compact','chevrolet','spark','Maryland',20583.00,NULL);
INSERT INTO VEHICLES
(vehicleVIN,vehicleType,vehicleMake,vehicleModel,vehicleWhereFrom,vehicleWholesaleCost,vehicleTradeID)
VALUES
('789456ERT0923RFB6','Midsize','ford','Taurus','washington, d.c.',25897.22,1);
INSERT INTO VEHICLES
(vehicleVIN,vehicleType,vehicleMake,vehicleModel,vehicleWhereFrom,vehicleWholesaleCost,vehicleTradeID)
VALUES
('1234567890QWERTYUIOP','fullsize','Lincoln','towncar','Virginia',44222.10,NULL);
INSERT INTO VEHICLES
(vehicleVIN,vehicleType,vehicleMake,vehicleModel,vehicleWhereFrom,vehicleWholesaleCost,vehicleTradeID)
VALUES
('WER234109TEO458GZ','SUV','Chevrolet','suburban','Maryland',52789.00,2);

ALTER TABLE VEHICLES RENAME TO OLTP_VEHICLES;

CREATE TABLE VEHICLES
(vehicleCode        VARCHAR(25) PRIMARY KEY,
vehicleDescription  VARCHAR(50) NOT NULL);

我也把这个放到SQL Fiddle如果有人想测试一些东西：http://sqlfiddle.com/#!4/2de3ae

谢谢！

Answer 1

经过大量研究、反复试验，当然还有@MatBailie 的帮助，终于弄明白了。这是我寻求的解决方案：

--Oracle sequence to populate primary key values in VEHICLES dimension table

DROP SEQUENCE SEQ_VEHICLES;
CREATE SEQUENCE SEQ_VEHICLES START WITH 1 INCREMENT BY 1;

CREATE OR REPLACE TRIGGER VEHICLES_PK
BEFORE INSERT ON VEHICLES FOR EACH ROW
BEGIN
SELECT SEQ_VEHICLES.NEXTVAL INTO :new.vehicleCode FROM DUAL;
END;
/

--PL/SQL Block to populate the description column via a cursor in a loop w/concatenation

DECLARE
CURSOR vehDesCur IS
    SELECT LOWER(vehicleMake) || ' ' || LOWER(vehicleModel)   AS vehicleDescription
    FROM OLTP_VEHICLES;
BEGIN
FOR oltp_data IN vehDesCur
LOOP
    INSERT INTO VEHICLES (vehicleDescription)
        SELECT oltp_data.vehicleDescription
        FROM dual
        WHERE NOT EXISTS
            (SELECT *
               FROM VEHICLES v
              WHERE v.vehicleDescription = oltp_data.vehicleDescription);
END LOOP;
END;
/

如何创建 ORACLE 序列以根据另一个 table 填充维度 Table

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