通过ORACLE函数，生成DIM_DATE表（自用）

在Oracle数据库中，创建一个名为DIM\_DATE的表通常用于数据仓库环境中，存储日期维度信息，如年、季度、月份、星期等。以下是一个使用PL/SQL函数来生成DIM\_DATE表的例子：

CREATE TABLE DIM_DATE (
  DATE_SK NUMBER NOT NULL,
  DATE_ID VARCHAR2(30) NOT NULL,
  CALENDAR_YEAR NUMBER,
  MONTH_OF_YEAR NUMBER,
  QUARTER NUMBER,
  WEEK_OF_YEAR NUMBER,
  DAY_OF_MONTH NUMBER,
  DAY_OF_WEEK NUMBER,
  IS_WEEKEND CHAR(1),
  CONSTRAINT PK_DIM_DATE PRIMARY KEY (DATE_SK)
);
/
 
CREATE OR REPLACE FUNCTION generate_dim_date_rows (
  start_date DATE, 
  end_date DATE
) RETURN NUMBER IS
  v_date DATE := start_date;
  v_date_sk NUMBER := 1;
BEGIN
  INSERT INTO DIM_DATE (DATE_SK, DATE_ID, CALENDAR_YEAR, MONTH_OF_YEAR, QUARTER, WEEK_OF_YEAR, DAY_OF_MONTH, DAY_OF_WEEK, IS_WEEKEND)
  VALUES (v_date_sk, TO_CHAR(v_date, 'YYYYMMDD'), TO_NUMBER(TO_CHAR(v_date, 'YYYY')), 
          TO_NUMBER(TO_CHAR(v_date, 'MM')), TO_NUMBER(TO_CHAR(v_date, 'Q')), 
          TO_NUMBER(TO_CHAR(v_date, 'IW')), TO_NUMBER(TO_CHAR(v_date, 'DD')), 
          TO_NUMBER(TO_CHAR(v_date, 'D')), 
          CASE WHEN TO_CHAR(v_date, 'D') IN ('6', '7') THEN 'Y' ELSE 'N' END);
 
  WHILE v_date <= end_date LOOP
    v_date_sk := v_date_sk + 1;
    v_date := v_date + 1;
    INSERT INTO DIM_DATE (DATE_SK, DATE_ID, CALENDAR_YEAR, MONTH_OF_YEAR, QUARTER, WEEK_OF_YEAR, DAY_OF_MONTH, DAY_OF_WEEK, IS_WEEKEND)
    VALUES (v_date_sk, TO_CHAR(v_date, 'YYYYMMDD'), TO_NUMBER(TO_CHAR(v_date, 'YYYY')), 
            TO_NUMBER(TO_CHAR(v_date, 'MM')), TO_NUMBER(TO_CHAR(v_date, 'Q')), 
            TO_NUMBER(TO_CHAR(v_date, 'IW')), TO_NUMBER(TO_CHAR(v_date, 'DD')), 
            TO_NUMBER(TO_CHAR(v_date, 'D')), 
            CASE WHEN TO_CHAR(v_date, 'D') IN ('6', '7') THEN 'Y' ELSE 'N' END);
  END LOOP;
  COMMIT;
  RETURN v_date_sk;
END;
/
 
BEGIN
  DBMS_OUTPUT.PUT_LINE('Number of rows inserted: ' || generate_dim_date_rows(TO_DATE('2010-01-01', 'YYYY-MM-DD'), TO_DATE('2020-12-31', 'YYYY-MM-DD')));
END;
/

这段代码首先创建了一个名为DIM\_DATE的表，包含了不同的日期信息字段。然后，它定义了一个PL/SQL函数generate_dim_date_rows，该函数接受起始日期和结束日期作为参数，并生成这个时间范围内每一天的日期维度数据。函数中使用了TO