Скачать или смотреть Gremlin Python How to use coalesce to get vertex if exists else insert

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Gremlin is a graph traversal language that is commonly used with Apache TinkerPop, a graph computing framework. In this tutorial, we will explore how to use Gremlin Python to interact with a graph database and specifically focus on the coalesce step for conditional operations. We'll demonstrate how to retrieve a vertex if it exists and, if not, insert a new one.
Before you begin, make sure you have the following installed:
To connect to Gremlin Server, use the following code:
Make sure to replace the gremlin_server variable with the appropriate WebSocket URL of your Gremlin Server.
The coalesce step in Gremlin allows you to try multiple traversals and return the result of the first successful one. This is useful for conditional operations, such as retrieving an existing vertex or inserting a new one if it doesn't exist.
Let's create a function that uses coalesce to achieve this:
This function takes the following parameters:
Let's use the function to retrieve an existing vertex or insert a new one:
In the first example, the function attempts to find a vertex with the name "John Doe." If it exists, the existing vertex is returned. In the second example, the function tries to find a vertex with the name "Jane Doe." If it doesn't exist, a new vertex is inserted with additional properties.
In this tutorial, you learned how to use Gremlin Python to perform conditional operations using the coalesce step. The provided function allows you to retrieve an existing vertex or insert a new one based on certain criteria. This can be particularly useful in scenarios where you want to ensure the existence of a vertex with specific properties in a graph database.
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