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Convert MS Access Northwind database to Oracle


Inside This Article
1How the data types in Access Northwind are converted to Oracle
2. Building Oracle Northwind database objects
   
3Queries to generate aggregated data for Oracle Northwind database

Building Oracle Northwind database objects



In part 2 of this article series, the scripts that are used to build Oracle Northwind objects are listed and explained. To get the full Oracle Northwind script and the image files, use the following links to download.

  • Click here to download the completed and fully normalized Oracle Northwind relational database script, including table data.
  • Click here to download the images for the Categories and Employees table.

The scripts for building tables, indexes, and constraints are shown below. Because there are foreign key relationships between these tables, they need to be built in the order they are listed here - build parent tables first and child tables at the end.

1. Categories table

The difference to the Categories table in Access is that the Picture column is defined as VARCHAR2 in Oracle. It only stores the image filename such as seafood.gif rather than a BLOB data type to store the actual image. The images are stored in file system. In the caller applications, such as standalone applications or web based applications, we can define the image folder's path as a global variable, then the image path and the image filename can be joined to get the full path to the image.

CREATE TABLE CATEGORIES
(
    CATEGORY_ID NUMBER(9) NOT NULL,
    CATEGORY_NAME VARCHAR2(15 BYTE) NOT NULL,
    DESCRIPTION VARCHAR2(2000 BYTE),
    PICTURE VARCHAR2(255 BYTE),
    CONSTRAINT PK_CATEGORIES PRIMARY KEY (CATEGORY_ID)
);

CREATE UNIQUE INDEX UIDX_CATEGORY_NAME ON CATEGORIES(CATEGORY_NAME);

CREATE SEQUENCE SEQ_NW_CATEGORIES  
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 9
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN CATEGORIES.CATEGORY_ID IS 'Number automatically assigned to a new category.';
COMMENT ON COLUMN CATEGORIES.CATEGORY_NAME IS 'Name of food category.';
COMMENT ON COLUMN CATEGORIES.PICTURE IS 'A picture representing the food category.';

2. Customers table

Customer_Code is a unique five-character code based on customers name. Unlike the Access Northwind database where Customer_Code was used as the primary key, Customer_ID was created as the primary key in Oracle. The advantage of doing it this way is that Customer_ID is a surrogate key that is NOT related to the business, and as such it's not affected by future changes in business rules or definitions. Customer_Code is still kept in the Oracle table with a unique index defined on it.

CREATE TABLE CUSTOMERS
(
    CUSTOMER_ID NUMBER(9) NOT NULL,
    CUSTOMER_CODE VARCHAR2(5 BYTE) NOT NULL,
    COMPANY_NAME VARCHAR2(40 BYTE) NOT NULL,
    CONTACT_NAME VARCHAR2(30 BYTE),
    CONTACT_TITLE VARCHAR2(30 BYTE),
    ADDRESS VARCHAR2(60 BYTE),
    CITY VARCHAR2(15 BYTE),
    REGION VARCHAR2(15 BYTE),
    POSTAL_CODE VARCHAR2(10 BYTE),
    COUNTRY VARCHAR2(15 BYTE),
    PHONE VARCHAR2(24 BYTE),
    FAX VARCHAR2(24 BYTE),
    CONSTRAINT PK_CUSTOMERS PRIMARY KEY (CUSTOMER_ID)
);

CREATE UNIQUE INDEX UIDX_CUSTOMERS_CODE ON CUSTOMERS(CUSTOMER_CODE);

CREATE INDEX IDX_CUSTOMERS_CITY ON CUSTOMERS(CITY);

CREATE INDEX IDX_CUSTOMERS_COMPANY_NAME ON CUSTOMERS(COMPANY_NAME);

CREATE INDEX IDX_CUSTOMERS_POSTAL_CODE ON CUSTOMERS(POSTAL_CODE);

CREATE INDEX IDX_CUSTOMERS_REGION ON CUSTOMERS(REGION);

CREATE SEQUENCE SEQ_NW_CUSTOMERS
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 92
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN CUSTOMERS.CUSTOMER_ID IS 'Unique five-character code based on customer name.';
COMMENT ON COLUMN CUSTOMERS.ADDRESS IS 'Street or post-office box.';
COMMENT ON COLUMN CUSTOMERS.REGION IS 'State or province.';
COMMENT ON COLUMN CUSTOMERS.PHONE IS 'Phone number includes country code or area code.';
COMMENT ON COLUMN CUSTOMERS.FAX IS 'Phone number includes country code or area code.';

3. Employees table

Employees table has a self referenced Foreign Key constraint which must be defined after the table is built, so it's put at the end of the script here as part of ALTER TABLE statement.

Employees table also has a built-in trigger for validating employee birthdate. As we mentioned in part 1 of this article series, because Oracle does not allow reference to sysdate function (also currval, nextval, rowid, etc.) in a check constraint, we created a trigger to do the validation instead.

Employees Photo column is also defined as VARCHAR2 to store the image filename rather than storing the actual image as a BLOB data type.

CREATE TABLE EMPLOYEES
(
    EMPLOYEE_ID NUMBER(9) NOT NULL,
    LASTNAME VARCHAR2(20 BYTE) NOT NULL,
    FIRSTNAME VARCHAR2(10 BYTE) NOT NULL,
    TITLE VARCHAR2(30 BYTE),
    TITLE_OF_COURTESY VARCHAR2(25 BYTE),
    BIRTHDATE DATE,
    HIREDATE DATE,
    ADDRESS VARCHAR2(60 BYTE),
    CITY VARCHAR2(15 BYTE),
    REGION VARCHAR2(15 BYTE),
    POSTAL_CODE VARCHAR2(10 BYTE),
    COUNTRY VARCHAR2(15 BYTE),
    HOME_PHONE VARCHAR2(24 BYTE),
    EXTENSION VARCHAR2(4 BYTE),
    PHOTO VARCHAR2(255 BYTE),
    NOTES VARCHAR2(2000 BYTE),
    REPORTS_TO NUMBER(9),
    CONSTRAINT PK_EMPLOYEES PRIMARY KEY (EMPLOYEE_ID)
);

CREATE INDEX IDX_EMPLOYEES_LASTNAME ON EMPLOYEES(LASTNAME);

CREATE INDEX IDX_EMPLOYEES_POSTAL_CODE ON EMPLOYEES(POSTAL_CODE);

-- Create a trigger to validate employee birthdate.
CREATE OR REPLACE TRIGGER TRG_EMP_BIRTHDATE
BEFORE INSERT OR UPDATE
OF BIRTHDATE
ON EMPLOYEES 
REFERENCING NEW AS NEW OLD AS OLD
FOR EACH ROW
begin
    if :New.birthdate > trunc(sysdate) then
          RAISE_APPLICATION_ERROR (num => -20000, msg => 'Birthdate cannot be in the future');
    end if;
end;

CREATE SEQUENCE SEQ_NW_EMPLOYEES
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 10
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN EMPLOYEES.EMPLOYEE_ID IS 'Number automatically assigned to new employee.';
COMMENT ON COLUMN EMPLOYEES.TITLE IS 'Employee''s title.';
COMMENT ON COLUMN EMPLOYEES.TITLE_OF_COURTESY IS 'Title used in salutations.';
COMMENT ON COLUMN EMPLOYEES.ADDRESS IS 'Street or post-office box.';
COMMENT ON COLUMN EMPLOYEES.REGION IS 'State or province.';
COMMENT ON COLUMN EMPLOYEES.HOME_PHONE IS 'Phone number includes country code or area code.';
COMMENT ON COLUMN EMPLOYEES.EXTENSION IS 'Internal telephone extension number.';
COMMENT ON COLUMN EMPLOYEES.PHOTO IS 'Picture of employee.';
COMMENT ON COLUMN EMPLOYEES.NOTES IS 'General information about employee''s background.';
COMMENT ON COLUMN EMPLOYEES.REPORTS_TO IS 'Employee''s supervisor.';

ALTER TABLE EMPLOYEES
ADD CONSTRAINT FK_REPORTS_TO FOREIGN KEY (REPORTS_TO) REFERENCES EMPLOYEES(EMPLOYEE_ID);

4. Suppliers table

Nothing is really special about this table.

CREATE TABLE SUPPLIERS
(
    SUPPLIER_ID NUMBER(9) NOT NULL,
    COMPANY_NAME VARCHAR2(40 BYTE) NOT NULL,
    CONTACT_NAME VARCHAR2(30 BYTE),
    CONTACT_TITLE VARCHAR2(30 BYTE),
    ADDRESS VARCHAR2(60 BYTE),
    CITY VARCHAR2(15 BYTE),
    REGION VARCHAR2(15 BYTE),
    POSTAL_CODE VARCHAR2(10 BYTE),
    COUNTRY VARCHAR2(15 BYTE),
    PHONE VARCHAR2(24 BYTE),
    FAX VARCHAR2(24 BYTE),
    HOME_PAGE VARCHAR2(500 BYTE),
    CONSTRAINT PK_SUPPLIERS PRIMARY KEY (SUPPLIER_ID)  
);

CREATE INDEX IDX_SUPPLIERS_COMPANY_NAME ON SUPPLIERS(COMPANY_NAME);

CREATE INDEX IDX_SUPPLIERS_POSTAL_CODE ON SUPPLIERS(POSTAL_CODE);

CREATE SEQUENCE SEQ_NW_SUPPLIERS
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 30
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN SUPPLIERS.SUPPLIER_ID IS 'Number automatically assigned to new supplier.';
COMMENT ON COLUMN SUPPLIERS.ADDRESS IS 'Street or post-office box.';
COMMENT ON COLUMN SUPPLIERS.REGION IS 'State or province.';
COMMENT ON COLUMN SUPPLIERS.PHONE IS 'Phone number includes country code or area code.';
COMMENT ON COLUMN SUPPLIERS.FAX IS 'Phone number includes country code or area code.';
COMMENT ON COLUMN SUPPLIERS.HOME_PAGE IS 'Supplier''s home page on World Wide Web.';

5. Shippers table

Nothing is worth mentioning either here.

CREATE TABLE SHIPPERS
(
    SHIPPER_ID NUMBER(9) NOT NULL,
    COMPANY_NAME VARCHAR2(40 BYTE) NOT NULL,
    PHONE VARCHAR2(24 BYTE),
    CONSTRAINT PK_SHIPPERS PRIMARY KEY (SHIPPER_ID)
);

CREATE SEQUENCE SEQ_NW_SHIPPERS
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 4
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN SHIPPERS.SHIPPER_ID IS 'Number automatically assigned to new shipper.';
COMMENT ON COLUMN SHIPPERS.COMPANY_NAME IS 'Name of shipping company.';
COMMENT ON COLUMN SHIPPERS.PHONE IS 'Phone number includes country code or area code.';

6. Products table (child table)

There are five check constraints defined in Products table. It also has two foreign key relationships to Categories and Suppliers table. There are 5 default constraints.

CREATE TABLE PRODUCTS
(
    PRODUCT_ID NUMBER(9) NOT NULL,
    PRODUCT_NAME VARCHAR2(40 BYTE) NOT NULL,
    SUPPLIER_ID NUMBER(9) NOT NULL,
    CATEGORY_ID NUMBER(9) NOT NULL,
    QUANTITY_PER_UNIT VARCHAR2(20 BYTE),
    UNIT_PRICE NUMBER(10,2) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_PRODUCTS_UNIT_PRICE CHECK (Unit_Price>=0),
    UNITS_IN_STOCK NUMBER(9) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_PRODUCTS_UNITS_IN_STOCK CHECK (Units_In_Stock>=0),
    UNITS_ON_ORDER NUMBER(9) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_PRODUCTS_UNITS_ON_ORDER CHECK (Units_On_Order>=0),
    REORDER_LEVEL NUMBER(9) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_PRODUCTS_REORDER_LEVEL CHECK (Reorder_Level>=0),
    DISCONTINUED CHAR(1 BYTE) DEFAULT 'N' NOT NULL 
    	CONSTRAINT CK_PRODUCTS_DISCONTINUED CHECK (Discontinued in ('Y','N')),
    CONSTRAINT PK_PRODUCTS PRIMARY KEY (PRODUCT_ID),
    CONSTRAINT FK_CATEGORY_ID FOREIGN KEY (CATEGORY_ID) REFERENCES CATEGORIES(CATEGORY_ID),
    CONSTRAINT FK_SUPPLIER_ID FOREIGN KEY (SUPPLIER_ID) REFERENCES SUPPLIERS(SUPPLIER_ID)  
);
  
CREATE INDEX IDX_PRODUCTS_CATEGORY_ID ON PRODUCTS(CATEGORY_ID);

CREATE INDEX IDX_PRODUCTS_SUPPLIER_ID ON PRODUCTS(SUPPLIER_ID);

CREATE SEQUENCE SEQ_NW_PRODUCTS
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 78
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;
  
COMMENT ON COLUMN PRODUCTS.PRODUCT_ID IS 'Number automatically assigned to new product.';
COMMENT ON COLUMN PRODUCTS.SUPPLIER_ID IS 'Same entry as in Suppliers table.';
COMMENT ON COLUMN PRODUCTS.CATEGORY_ID IS 'Same entry as in Categories table.';
COMMENT ON COLUMN PRODUCTS.QUANTITY_PER_UNIT IS '(e.g., 24-count case, 1-liter bottle).';
COMMENT ON COLUMN PRODUCTS.REORDER_LEVEL IS 'Minimum units to maintain in stock.';
COMMENT ON COLUMN PRODUCTS.DISCONTINUED IS 'Yes means item is no longer available.';

7. Orders table (child table)

Orders table has 3 foreign key relationships to Customers, Employees, and Shippers table. There is 1 default constraint.

CREATE TABLE ORDERS
(
    ORDER_ID NUMBER(9) NOT NULL,
    CUSTOMER_ID NUMBER(9) NOT NULL,
    EMPLOYEE_ID NUMBER(9) NOT NULL,
    ORDER_DATE DATE NOT NULL,
    REQUIRED_DATE DATE,
    SHIPPED_DATE DATE,
    SHIP_VIA NUMBER(9),
    FREIGHT NUMBER(10,2) DEFAULT 0,
    SHIP_NAME VARCHAR2(40 BYTE),
    SHIP_ADDRESS VARCHAR2(60 BYTE),
    SHIP_CITY VARCHAR2(15 BYTE),
    SHIP_REGION VARCHAR2(15 BYTE),
    SHIP_POSTAL_CODE VARCHAR2(10 BYTE),
    SHIP_COUNTRY VARCHAR2(15 BYTE),
    CONSTRAINT PK_ORDERS PRIMARY KEY (ORDER_ID),
    CONSTRAINT FK_CUSTOMER_ID FOREIGN KEY (CUSTOMER_ID) REFERENCES CUSTOMERS(CUSTOMER_ID),  
    CONSTRAINT FK_EMPLOYEE_ID FOREIGN KEY (EMPLOYEE_ID) REFERENCES EMPLOYEES(EMPLOYEE_ID),  
    CONSTRAINT FK_SHIPPER_ID FOREIGN KEY (SHIP_VIA) REFERENCES SHIPPERS(SHIPPER_ID)  
);

CREATE INDEX IDX_ORDERS_CUSTOMER_ID ON ORDERS(CUSTOMER_ID);

CREATE INDEX IDX_ORDERS_EMPLOYEE_ID ON ORDERS(EMPLOYEE_ID);

CREATE INDEX IDX_ORDERS_SHIPPER_ID ON ORDERS(SHIP_VIA);

CREATE INDEX IDX_ORDERS_ORDER_DATE ON ORDERS(ORDER_DATE);

CREATE INDEX IDX_ORDERS_SHIPPED_DATE ON ORDERS(SHIPPED_DATE);

CREATE INDEX IDX_ORDERS_SHIP_POSTAL_CODE ON ORDERS(SHIP_POSTAL_CODE);

CREATE SEQUENCE SEQ_NW_ORDERS
    MINVALUE 1
    MAXVALUE 999999999999999999999999999
    START WITH 11018
    INCREMENT BY 1
    NOCYCLE
    NOCACHE
    NOORDER;

COMMENT ON COLUMN ORDERS.ORDER_ID IS 'Unique order number.';
COMMENT ON COLUMN ORDERS.CUSTOMER_ID IS 'Same entry as in Customers table.';
COMMENT ON COLUMN ORDERS.EMPLOYEE_ID IS 'Same entry as in Employees table.';
COMMENT ON COLUMN ORDERS.SHIP_VIA IS 'Same as Shipper ID in Shippers table.';
COMMENT ON COLUMN ORDERS.SHIP_NAME IS 'Name of person or company to receive the shipment.';
COMMENT ON COLUMN ORDERS.SHIP_ADDRESS IS 'Street address only -- no post-office box allowed.';
COMMENT ON COLUMN ORDERS.SHIP_REGION IS 'State or province.';

8. Order_Details table (child table)

Orders_Details table has 2 foreign key relationships to Orders and Products table. It also has 3 check constraints for Unit_Price, Quantity, and Discount column. There are 3 default constraints.

CREATE TABLE ORDER_DETAILS
(
    ORDER_ID NUMBER(9) NOT NULL,
    PRODUCT_ID NUMBER(9) NOT NULL,
    UNIT_PRICE NUMBER(10,2) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_ORDER_DETAILS_UNIT_PRICE CHECK (Unit_Price>=0),
    QUANTITY NUMBER(9) DEFAULT 1 NOT NULL 
    	CONSTRAINT CK_ORDER_DETAILS_QUANTITY CHECK (Quantity>0),
    DISCOUNT NUMBER(4,2) DEFAULT 0 NOT NULL 
    	CONSTRAINT CK_ORDER_DETAILS_DISCOUNT CHECK (Discount between 0 and 1),
    CONSTRAINT PK_ORDER_DETAILS PRIMARY KEY (ORDER_ID, PRODUCT_ID),
    CONSTRAINT FK_ORDER_ID FOREIGN KEY (ORDER_ID) REFERENCES ORDERS (ORDER_ID),
    CONSTRAINT FK_PRODUCT_ID FOREIGN KEY (PRODUCT_ID) REFERENCES PRODUCTS (PRODUCT_ID)
);

CREATE INDEX IDX_ORDER_DETAILS_ORDER_ID ON ORDER_DETAILS(ORDER_ID);
CREATE INDEX IDX_ORDER_DETAILS_PRODUCT_ID ON ORDER_DETAILS(PRODUCT_ID);
COMMENT ON COLUMN ORDER_DETAILS.ORDER_ID IS 'Same as Order ID in Orders table.';
COMMENT ON COLUMN ORDER_DETAILS.PRODUCT_ID IS 'Same as Product ID in Products table.';

In what order to drop the tables so that they can be rebuilt

SQL below shows the correct order to drop the tables. Because there are foreign key relationships defined, we can't drop the parent tables before child tables. Referential integrity enforces a parent table can't be dropped if there are still foreign keys in the child table references the parent keys in parent table.

Note that, when a table is dropped, all the related objects to that table are automatically dropped too, except for the sequence objects. So we have to drop the sequences separately.

-- Drop all tables and their indexes, constraints, and triggers.
DROP TABLE ORDER_DETAILS PURGE;
DROP TABLE ORDERS PURGE;
DROP TABLE PRODUCTS PURGE;
DROP TABLE SUPPLIERS PURGE;
DROP TABLE CATEGORIES PURGE;
DROP TABLE CUSTOMERS PURGE;
DROP TABLE EMPLOYEES PURGE;
DROP TABLE SHIPPERS PURGE;

-- Drop all sequences.
DROP SEQUENCE SEQ_NW_CATEGORIES;
DROP SEQUENCE SEQ_NW_CUSTOMERS;
DROP SEQUENCE SEQ_NW_EMPLOYEES;
DROP SEQUENCE SEQ_NW_ORDERS;
DROP SEQUENCE SEQ_NW_PRODUCTS;
DROP SEQUENCE SEQ_NW_SHIPPERS;
DROP SEQUENCE SEQ_NW_SUPPLIERS;

The scripts that insert data to the tables are not listed on this page. Please download the full script by using the link shown at the beginning of this page. In next part of this article series, we're going to look at how the queries in Access Northwind database are converted to Oracle queries.


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Inside This Article
1How the data types in Access Northwind are converted to Oracle
2. Building Oracle Northwind database objects
   
3Queries to generate aggregated data for Oracle Northwind database
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