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datamart updated

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StewKI
2026-05-17 21:23:55 +02:00
parent 6c70628616
commit 348a074a3a
1 changed files with 60 additions and 14 deletions
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74
sql/datamart_schema.sql
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@@ -1,9 +1,39 @@
-- ============================================================================= -- =============================================================================
-- HOTEL RESERVATIONS — DATA MART (STAR SCHEMA) -- HOTEL RESERVATIONS — DATA MART (STAR SCHEMA)
-- Target: Oracle (university lab schema) -- Target: Oracle (university lab schema)
-- Based on A.24 Revenue Data Mart — Dimensional Modelling by Example
-- ============================================================================= -- =============================================================================
-- -----------------------------------------------------------------------------
-- ETL CONTROL TABLE
-- Tracks incremental load watermarks per entity.
-- -----------------------------------------------------------------------------
CREATE TABLE ETL_WATERMARK (
entity_name VARCHAR2(50) NOT NULL,
last_key NUMBER(20,0) DEFAULT 0 NOT NULL,
last_run_ts TIMESTAMP DEFAULT SYSTIMESTAMP,
CONSTRAINT pk_etl_wm PRIMARY KEY (entity_name)
);
INSERT INTO ETL_WATERMARK (entity_name, last_key) VALUES ('FACT_ROOM_BOOKING', 0);
COMMIT;
-- -----------------------------------------------------------------------------
-- STAGING TABLES
-- NiFi loads raw MySQL data here first; SCD logic runs in pure SQL after.
-- Truncated at the start of each ETL run.
-- -----------------------------------------------------------------------------
CREATE TABLE STG_HOTEL (
hotel_id NUMBER(10,0) NOT NULL,
chain_code VARCHAR2(10),
country_code CHAR(2) NOT NULL,
star_code NUMBER(1,0) NOT NULL,
code VARCHAR2(20) NOT NULL,
name VARCHAR2(150) NOT NULL,
city VARCHAR2(100) NOT NULL
);
-- ----------------------------------------------------------------------------- -- -----------------------------------------------------------------------------
-- DIMENSION TABLES -- DIMENSION TABLES
-- ----------------------------------------------------------------------------- -- -----------------------------------------------------------------------------
@@ -21,12 +51,13 @@ CREATE TABLE DIM_DATE (
day_name VARCHAR2(10) NOT NULL, day_name VARCHAR2(10) NOT NULL,
is_weekend NUMBER(1,0) NOT NULL, is_weekend NUMBER(1,0) NOT NULL,
is_business_day NUMBER(1,0) NOT NULL, is_business_day NUMBER(1,0) NOT NULL,
season VARCHAR2(10) NOT NULL, -- Peak / High / Low / Off season VARCHAR2(10) NOT NULL,
CONSTRAINT pk_dim_date PRIMARY KEY (date_key), CONSTRAINT pk_dim_date PRIMARY KEY (date_key),
CONSTRAINT ck_dim_date_wknd CHECK (is_weekend IN (0,1)), CONSTRAINT ck_dim_date_wknd CHECK (is_weekend IN (0,1)),
CONSTRAINT ck_dim_date_bday CHECK (is_business_day IN (0,1)) CONSTRAINT ck_dim_date_bday CHECK (is_business_day IN (0,1))
); );
-- SCD Type 1 — country attributes are stable; just overwrite if anything changes
CREATE TABLE DIM_COUNTRY ( CREATE TABLE DIM_COUNTRY (
country_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, country_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
country_id NUMBER(10,0) NOT NULL, country_id NUMBER(10,0) NOT NULL,
@@ -37,6 +68,7 @@ CREATE TABLE DIM_COUNTRY (
CONSTRAINT uq_dim_cntry_id UNIQUE (country_id) CONSTRAINT uq_dim_cntry_id UNIQUE (country_id)
); );
-- SCD Type 1 — star rating lookup, never changes
CREATE TABLE DIM_STAR_RATING ( CREATE TABLE DIM_STAR_RATING (
star_rating_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, star_rating_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
star_rating_id NUMBER(10,0) NOT NULL, star_rating_id NUMBER(10,0) NOT NULL,
@@ -46,6 +78,7 @@ CREATE TABLE DIM_STAR_RATING (
CONSTRAINT uq_dim_star_id UNIQUE (star_rating_id) CONSTRAINT uq_dim_star_id UNIQUE (star_rating_id)
); );
-- SCD Type 1 — chain name/code rarely changes; overwrite
CREATE TABLE DIM_HOTEL_CHAIN ( CREATE TABLE DIM_HOTEL_CHAIN (
hotel_chain_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, hotel_chain_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
hotel_chain_id NUMBER(10,0) NOT NULL, hotel_chain_id NUMBER(10,0) NOT NULL,
@@ -55,22 +88,31 @@ CREATE TABLE DIM_HOTEL_CHAIN (
CONSTRAINT uq_dim_chain_id UNIQUE (hotel_chain_id) CONSTRAINT uq_dim_chain_id UNIQUE (hotel_chain_id)
); );
-- SCD Type 2 — hotels can change star rating or chain affiliation over time.
-- source_hotel_id is the natural key from MySQL; hotel_key is the surrogate.
-- One hotel can have multiple rows; IS_CURRENT=1 row is the active version.
-- FACT_ROOM_BOOKING links to the hotel version current at check-in date.
CREATE TABLE DIM_HOTEL ( CREATE TABLE DIM_HOTEL (
hotel_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, hotel_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
hotel_id NUMBER(10,0) NOT NULL, source_hotel_id NUMBER(10,0) NOT NULL,
hotel_chain_key NUMBER(10,0), hotel_chain_key NUMBER(10,0),
country_key NUMBER(10,0) NOT NULL, country_key NUMBER(10,0) NOT NULL,
star_rating_key NUMBER(10,0) NOT NULL, star_rating_key NUMBER(10,0) NOT NULL,
code VARCHAR2(20) NOT NULL, code VARCHAR2(20) NOT NULL,
name VARCHAR2(150) NOT NULL, name VARCHAR2(150) NOT NULL,
city VARCHAR2(100) NOT NULL, city VARCHAR2(100) NOT NULL,
CONSTRAINT pk_dim_hotel PRIMARY KEY (hotel_key), -- SCD2 versioning
CONSTRAINT uq_dim_hotel_id UNIQUE (hotel_id), effective_date DATE NOT NULL,
CONSTRAINT fk_dh_chain FOREIGN KEY (hotel_chain_key) REFERENCES DIM_HOTEL_CHAIN (hotel_chain_key), expiry_date DATE,
CONSTRAINT fk_dh_country FOREIGN KEY (country_key) REFERENCES DIM_COUNTRY (country_key), is_current NUMBER(1,0) DEFAULT 1 NOT NULL,
CONSTRAINT fk_dh_star FOREIGN KEY (star_rating_key) REFERENCES DIM_STAR_RATING (star_rating_key) CONSTRAINT pk_dim_hotel PRIMARY KEY (hotel_key),
CONSTRAINT ck_dh_current CHECK (is_current IN (0,1)),
CONSTRAINT fk_dh_chain FOREIGN KEY (hotel_chain_key) REFERENCES DIM_HOTEL_CHAIN (hotel_chain_key),
CONSTRAINT fk_dh_country FOREIGN KEY (country_key) REFERENCES DIM_COUNTRY (country_key),
CONSTRAINT fk_dh_star FOREIGN KEY (star_rating_key) REFERENCES DIM_STAR_RATING (star_rating_key)
); );
-- SCD Type 1 — room type/floor rarely changes; upsert is sufficient
CREATE TABLE DIM_ROOM ( CREATE TABLE DIM_ROOM (
room_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, room_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
room_id NUMBER(10,0) NOT NULL, room_id NUMBER(10,0) NOT NULL,
@@ -87,6 +129,7 @@ CREATE TABLE DIM_ROOM (
CONSTRAINT ck_dim_room_smk CHECK (smoking_yn IN (0,1)) CONSTRAINT ck_dim_room_smk CHECK (smoking_yn IN (0,1))
); );
-- SCD Type 1 — guest contact details are overwritten if they change
CREATE TABLE DIM_GUEST ( CREATE TABLE DIM_GUEST (
guest_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, guest_key NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
guest_id NUMBER(10,0) NOT NULL, guest_id NUMBER(10,0) NOT NULL,
@@ -102,11 +145,13 @@ CREATE TABLE DIM_GUEST (
-- FACT TABLE -- FACT TABLE
-- ----------------------------------------------------------------------------- -- -----------------------------------------------------------------------------
-- Grain: one row per room_booking -- Grain: one row per room_booking.
-- Revenue measures: nightly_rate, total_amount, nights_stayed -- source_rb_id: natural key from MySQL — used for idempotent incremental loads.
-- hotel_key: points to the DIM_HOTEL version active at check-in (SCD2 lookup).
CREATE TABLE FACT_ROOM_BOOKING ( CREATE TABLE FACT_ROOM_BOOKING (
fact_id NUMBER(10,0) GENERATED ALWAYS AS IDENTITY, fact_id NUMBER(10,0) GENERATED ALWAYS AS IDENTITY,
-- foreign keys source_rb_id NUMBER(10,0) NOT NULL,
-- dimension FKs
hotel_key NUMBER(10,0) NOT NULL, hotel_key NUMBER(10,0) NOT NULL,
hotel_chain_key NUMBER(10,0), hotel_chain_key NUMBER(10,0),
room_key NUMBER(10,0) NOT NULL, room_key NUMBER(10,0) NOT NULL,
@@ -115,19 +160,20 @@ CREATE TABLE FACT_ROOM_BOOKING (
star_rating_key NUMBER(10,0) NOT NULL, star_rating_key NUMBER(10,0) NOT NULL,
checkin_date_key NUMBER(8,0) NOT NULL, checkin_date_key NUMBER(8,0) NOT NULL,
checkout_date_key NUMBER(8,0) NOT NULL, checkout_date_key NUMBER(8,0) NOT NULL,
-- degenerate dimensions -- degenerate dimension
booking_status VARCHAR2(20) NOT NULL, booking_status VARCHAR2(20) NOT NULL,
-- measures -- measures
nights_stayed NUMBER(4,0) NOT NULL, nights_stayed NUMBER(4,0) NOT NULL,
nightly_rate NUMBER(10,2) NOT NULL, nightly_rate NUMBER(10,2) NOT NULL,
total_amount NUMBER(12,2) NOT NULL, total_amount NUMBER(12,2) NOT NULL,
CONSTRAINT pk_fact_rb PRIMARY KEY (fact_id), CONSTRAINT pk_fact_rb PRIMARY KEY (fact_id),
CONSTRAINT uq_fact_rb_src UNIQUE (source_rb_id),
CONSTRAINT fk_frb_hotel FOREIGN KEY (hotel_key) REFERENCES DIM_HOTEL (hotel_key), CONSTRAINT fk_frb_hotel FOREIGN KEY (hotel_key) REFERENCES DIM_HOTEL (hotel_key),
CONSTRAINT fk_frb_chain FOREIGN KEY (hotel_chain_key) REFERENCES DIM_HOTEL_CHAIN (hotel_chain_key), CONSTRAINT fk_frb_chain FOREIGN KEY (hotel_chain_key) REFERENCES DIM_HOTEL_CHAIN (hotel_chain_key),
CONSTRAINT fk_frb_room FOREIGN KEY (room_key) REFERENCES DIM_ROOM (room_key), CONSTRAINT fk_frb_room FOREIGN KEY (room_key) REFERENCES DIM_ROOM (room_key),
CONSTRAINT fk_frb_guest FOREIGN KEY (guest_key) REFERENCES DIM_GUEST (guest_key), CONSTRAINT fk_frb_guest FOREIGN KEY (guest_key) REFERENCES DIM_GUEST (guest_key),
CONSTRAINT fk_frb_country FOREIGN KEY (country_key) REFERENCES DIM_COUNTRY (country_key), CONSTRAINT fk_frb_country FOREIGN KEY (country_key) REFERENCES DIM_COUNTRY (country_key),
CONSTRAINT fk_frb_star FOREIGN KEY (star_rating_key) REFERENCES DIM_STAR_RATING (star_rating_key), CONSTRAINT fk_frb_star FOREIGN KEY (star_rating_key) REFERENCES DIM_STAR_RATING (star_rating_key),
CONSTRAINT fk_frb_checkin FOREIGN KEY (checkin_date_key) REFERENCES DIM_DATE (date_key), CONSTRAINT fk_frb_checkin FOREIGN KEY (checkin_date_key) REFERENCES DIM_DATE (date_key),
CONSTRAINT fk_frb_checkout FOREIGN KEY (checkout_date_key) REFERENCES DIM_DATE (date_key) CONSTRAINT fk_frb_checkout FOREIGN KEY (checkout_date_key) REFERENCES DIM_DATE (date_key)
); );