Graph

blobhub.types.orientdb.Graph is the typed module for blobhub.graph.orientdb blobs. Each revision of such a blob is its own OrientDB database, and Graph runs one OrientDB SQL statement at a time against it. That is the module’s whole surface.

import blobhub
from blobhub.types.orientdb import Graph

hub = blobhub.connect()
graph = Graph(hub.blob("acme", "knowledge").revision())    # or revision.typed()

graph.execute("CREATE VERTEX V SET name = 'fox'", write=True)
result = graph.execute("SELECT FROM V WHERE name = :name", {"name": "fox"})
for vertex in result.vertices:
    print(vertex["@rid"], vertex["@class"], vertex.get("name"))

Graph(revision) raises TypeMismatch when the revision’s blob is not a graph blob.

Execute

graph.execute(statement, params=None, *, write=False) runs one statement and returns a GraphResult with two lists, vertices and edges. Each item is an OrientDB record as a dict, carrying its @rid and @class.

	A read	A write
How	`write=False`, the default	`write=True`
Sent to	the revision’s query channel	the command channel
Statements	exactly one `SELECT`, `TRAVERSE` or `MATCH`	any statement
Revisions	a draft or a committed one	a draft only

A read refuses anything else. A statement that is not one SELECT, TRAVERSE or MATCH raises CommandError with error mutating_command_in_query_mode, before it reaches OrientDB. The message adds that write=True sends it through the command channel.
A write needs a draft. A committed revision raises Conflict with error revision_not_writable.
params fills placeholders: a dict for named ones (:name), a list for positional ones (?).
A statement returns at most 50 records, with OrientDB’s fetch plan *:1. Use SKIP and LIMIT in the statement to page through more.
An empty statement raises ValueError before any request.

Errors

When OrientDB refuses a statement, the message reads OrientDB refused the statement: <reason>, and the full detail is in error.details.

Error	When
`CommandError` `invalid_query`	OrientDB refused the statement.
`CommandError` `mutating_command_in_query_mode`	A read was not one `SELECT`, `TRAVERSE` or `MATCH`.
`Conflict` `revision_not_writable`	A write against a committed revision.
`ServerError` `graph_store_unavailable`	The revision’s database could not be opened.

A read is retried after a server error or a network failure; a write is retried only when it never reached the platform, so a CREATE VERTEX that timed out is never sent twice. It may still have run once: check before you repeat it. See Errors and retries.

Python SDK

Execute

Errors

See also

​Execute

​Errors

​See also

Execute

Errors

See also