Create Your First ERD¶

In this tutorial, you will design a simple e-commerce data model from scratch. By the end, you'll have learned all of ThinkERD's core workflows.

The ERD We'll Build¶

┌──────────┐       ┌──────────┐       ┌──────────┐
│ Customer │──────<│  Order   │──────<│Order Item│
│          │       │          │       │          │
└──────────┘       └──────────┘       └──────────┘
                                           │
                                           │
                                      ┌──────────┐
                                      │ Product  │
                                      │          │
                                      └──────────┘

• Customer: E-commerce member information
• Order: Customer's order records
• Order Item: Individual product items within an order
• Product: Product information for sale

Step 1. Create a Project¶

Enter Your Workspace¶

After logging in, your Workspace is displayed. A workspace is the top-level unit for managing projects.

Create a Project¶

1. Click the New Project button
2. Enter the project name: E-Commerce
3. Click Create

Open a Diagram¶

When you create a project, a default diagram is automatically generated. Click the diagram to open the ERD Canvas.

Workspace
  └─ Project (E-Commerce)
      └─ Diagram (Default)      ← You are here

Step 2. Create Entities¶

First Entity: Customer¶

1. Click the Add Entity button in the top toolbar
2. A new entity appears on the canvas
3. Double-click to open the edit dialog

1. Fill in the following:

1. Add columns:

1. Click Save

Create Remaining Entities¶

Create the remaining 3 entities using the same method:

Step 3. Define Relationships¶

Now create relationships between entities.

Customer → Order (1:N, Non-identifying)¶

"One customer can place multiple orders"

1. Drag the PK (Customer No) handle from the Customer entity
2. Drop it onto the surface of the Order entity
3. FK column Customer No (CUST_NO) is automatically added to the Order entity
4. The relationship line is displayed with dashed line + Crow's Foot

Customer ┅┅┅┅─────< Order
              (FK: CUST_NO)

Why non-identifying (dashed)? — The order does not include the customer number in its PK, so it can exist as an independent row.

Order → Order Item (1:N, Identifying)¶

"One order contains multiple item entries"

1. Drag the PK handle from Order and connect it to Order Item
2. FK column Order No (ORD_NO) is added to Order Item and becomes part of the PK
3. The relationship line is displayed with solid line + Crow's Foot

Order ━━━━━━━< Order Item
        (FK+PK: ORD_NO)

Why identifying (solid)? — Order Item has a composite PK of (Order No, Order Item Seq). An order item cannot exist without an order.

Product → Order Item (1:N, Non-identifying)¶

"One product can appear in multiple order items"

1. Drag the PK handle from Product and connect it to Order Item
2. FK column Product Code (PROD_CD) is added to Order Item

Step 4. Review the Model¶

Switch View Modes¶

Once the model is complete, review it from different perspectives.

Arrange the Layout¶

• Drag entities into a logical order
• Use Smart Guides for alignment
• If needed, use Zones to define domain boundaries

Step 5. Export SQL¶

Extract DDL¶

1. Go to Menu > File > Export as SQL
2. Select the target DBMS (e.g., Oracle)
3. Review the DDL preview
4. Save as a file or copy to clipboard

Generated DDL (Oracle Example)¶

-- ===================================
-- E-Commerce ERD — DDL (Oracle)
-- ===================================

CREATE TABLE CUSTOMER (
    CUST_NO   VARCHAR2(20) NOT NULL,
    CUST_NM   VARCHAR2(100) NOT NULL,
    EMAIL     VARCHAR2(200) NOT NULL,
    PHONE     VARCHAR2(20),
    REG_DT    DATE NOT NULL,
    CONSTRAINT PK_CUSTOMER PRIMARY KEY (CUST_NO)
);

CREATE TABLE PRODUCT (
    PROD_CD   VARCHAR2(20) NOT NULL,
    PROD_NM   VARCHAR2(200) NOT NULL,
    PRC       NUMBER(18,2) NOT NULL,
    CATEGORY  VARCHAR2(50),
    CONSTRAINT PK_PRODUCT PRIMARY KEY (PROD_CD)
);

CREATE TABLE ORD (
    ORD_NO    VARCHAR2(20) NOT NULL,
    CUST_NO   VARCHAR2(20) NOT NULL,
    ORD_DT    DATE NOT NULL,
    ORD_AMT   NUMBER(18,2) NOT NULL,
    ORD_STAT  VARCHAR2(10) NOT NULL,
    CONSTRAINT PK_ORD PRIMARY KEY (ORD_NO),
    CONSTRAINT FK_ORD_CUST
      FOREIGN KEY (CUST_NO) REFERENCES CUSTOMER (CUST_NO)
);

CREATE TABLE ORD_DTL (
    ORD_NO        VARCHAR2(20) NOT NULL,
    ORD_DTL_SEQ   NUMBER(5) NOT NULL,
    PROD_CD       VARCHAR2(20) NOT NULL,
    QTY           NUMBER(10) NOT NULL,
    UNIT_PRC      NUMBER(18,2) NOT NULL,
    CONSTRAINT PK_ORD_DTL PRIMARY KEY (ORD_NO, ORD_DTL_SEQ),
    CONSTRAINT FK_ORD_DTL_ORD
      FOREIGN KEY (ORD_NO) REFERENCES ORD (ORD_NO),
    CONSTRAINT FK_ORD_DTL_PROD
      FOREIGN KEY (PROD_CD) REFERENCES PRODUCT (PROD_CD)
);

Tutorial Complete! 🎉¶

Congratulations! You've accomplished the following:

• Created a project and diagram
• Defined 4 entities with columns
• Set up identifying/non-identifying relationships
• Switched view modes (logical/physical/combined)
• Exported SQL DDL

Next Steps¶