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Database Operations

Syncing data across the mesh is an entirely separate process from CRUD, involving replicating documents across different databases rather than interacting with a single datastore.

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Creating Documents

To insert a document, call the EXECUTE API method against the ditto.store object and include an INSERT INTO query that specifies the document to be inserted.

For example, the following snippet demonstrates how to insert a new document with a single field “color” set to “blue”:

To create multiple documents efficiently, batch your CREATE operations in a single operation.

If desired, supply a document ID in your creation request; otherwise, Ditto automatically generates and assigns one.

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Inserting Multiple Documents

To create multiple documents in a single operation, use the INSERT INTO operation as follows:

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Identifying Documents

Unless manually supplied, Ditto automatically generates and assigns the new document a 128‑bit Universally Unique Identifier (UUID).

The document identifier is represented as _id and serves as the primary key for the document.

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Retrieving Document IDs

To access the IDs of the documents affected by the INSERTION INTO operation, call the mutatedDocumentIDs method on the result object after the insertion like this:

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Supplying String IDs

When creating a document, you can assign it a custom ID. This custom ID can be generated using a single string value or a combination of two or more string values.

This flexibility in structuring document identifiers allows you to customize document IDs to your specific requirements, use cases, or standard naming conventions.

The following snippet demonstrates a new document assigned the custom ID “123”.

Following is the new 123 document that results:

{
  "_id": "123",
  "color": "blue"
}

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Forming Composite Keys

The following demonstrates combining the vin and make fields to form the composite key:

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Creating Attachments

There are two separate steps in the process of creating an attachment:

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Initiating ATTACHMENT Objects

To create the ATTACHMENT object that encodes the actual contents of the file to store externally, call the newAttachment method on thestorenamespace.

If desired, enclose extra information about the attachment, such as name and description. This metadata is useful for attachment fetching operations.

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Adding Optional Metadata

If you want to include information about the attachment, such as the attachment filename, as shown in the following snippet, a description, and other relevant details, enclose it in a metadata object as key-value pairs.

For example, in the following snippet, the metadata property encapsulates the name of the attachment, as well as its description:

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Referencing Attachment Tokens

After creating and storing a new attachment object in Ditto, you receive an attachment token as part of the response.

The following snippet demonstrates how to create a new document object containing a new attachment, and then insert it into the cars collection:

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Creating MAPs

There are two ways to create a MAP structure within a document:

• In an INSERT operation — Create a new document and nest it with this set of fields.
• In an UPDATE operation — If the MAP does not exist, create it. (See UPDATE)

To represent a highly complex data structure in a MAP, consider embedding it with an additional MAP. Embedding a MAP within a MAP establishes an additional hierarchy.

The decision to use deeply embedded MAPS in a single document or opt for a flat model depends on your requirements, relationships between data, and tolerance for certain tradeoffs.

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Inserting to Create a MAP

When inserting a new document in Ditto, you can define a field as a MAP and include the structure of key-value pairs nested within it — a two-in-one approach. For example:

Another method to creating a MAP within a document is to perform an UPDATE operation.

In the UPDATE approach, you set the structure of key-value pairs and specify the document ID for storage.

For example, this statement creates the MAP structure — unless it already exists — setting a single key-value pair of color is red within the properties MAP for the document with the ID 123 in the cars collection:

UPDATE COLLECTION cars (properties MAP) SET properties -> ( color = 'red' ) WHERE \_id = '123'