Indexed DB: To provide a key or not to provide a key

I am currently busy writing a little framework around the Indexed DB API to make it easier to use Indexed DB. One of the things I was struggling with was when the key parameter must or mustn’t be provided. So I tested every possible combinations.

For this I created 4 object stores with different combinations:

• Object store 1: KeyPath: “Id”, autoIncrement = true
• Object store 2: KeyPath: undefined, autoIncrement = true
• Object store 3: KeyPath: “Id”, autoIncrement = false
• Object store 4: KeyPath: undefined, autoIncrement = false

Next, I tried adding four different combinations, and here are the results.

Add/Put parameters		Object store configuration
Value	Key	Object store 1	Object store 2	Object store 3	Object store 4
{ Name: "test" }	undefined	successful	successful	failed	failed
{ Id: 1, Name: "test" }	undefined	successful	successful	successful	failed
{ Name: "test" }	1	failed	successful	failed	successful
{ Id: 1, Name: "test" }	1	failed	successful	failed	successful

 

Conclusion

1. When a KeyPath is defined, the key parameter must be undefined
2. When no KeyPath is defined and there is no autoIncrement, a key must be provided
3. When no KeyPath is defined and there is autoIncrement, a key can be provided
4. When a KeyPath is defined and there is no autoIncrement, an attribute with the name of the KeyPath must be present.