Download Graph Db
Palmira Iman
Data to initialize graph. If None (default) an emptygraph is created. The data can be any format that is supportedby the to_networkx_graph() function, currently including edge list,dict of dicts, dict of lists, NetworkX graph, 2D NumPy array, SciPysparse matrix, or PyGraphviz graph.
Each graph, node, and edge can hold key/value attribute pairsin an associated attribute dictionary (the keys must be hashable).By default these are empty, but can be added or changed usingadd_edge, add_node or direct manipulation of the attributedictionaries named graph, node and edge respectively.
Warning: we protect the graph data structure by making G.edges aread-only dict-like structure. However, you can assign to attributesin e.g. G.edges[1, 2]. Thus, use 2 sets of brackets to add/changedata attributes: G.edges[1, 2]['weight'] = 4(For multigraphs: MG.edges[u, v, key][name] = value).
Simple graph information is obtained using object-attributes and methods.Reporting typically provides views instead of containers to reduce memoryusage. The views update as the graph is updated similarly to dict-views.The objects nodes, edges and adj provide access to data attributesvia lookup (e.g. nodes[n], edges[u, v], adj[u][v]) and iteration(e.g. nodes.items(), nodes.data('color'),nodes.data('color', default='blue') and similarly for edges)Views exist for nodes, edges, neighbors()/adj and degree.
Each of these three dicts can be replaced in a subclass by a user defineddict-like object. In general, the dict-like features should bemaintained but extra features can be added. To replace one of thedicts create a new graph class by changing the class(!) variableholding the factory for that dict-like structure.
dbt actively builds the graph variable during the parsing phase ofrunning dbt projects, so some properties of the graph context variable will bemissing or incorrect during parsing. Please read the information below carefullyto understand how to effectively use this variable.
The model entries in the graph dictionary will be incomplete or incorrectduring parsing. If accessing the models in your project via the graphvariable, be sure to use the execute flag to ensure that this codeonly executes at run-time and not at parse-time. Do not use the graph variableto build your DAG, as the resulting dbt behavior will be undefined and likelyincorrect. Example usage:
This document describes the use of HTTP operations for the purpose of managing a collection of RDF graphs. This interface is an alternative to the SPARQL 1.1 Update protocol. Most of the operations defined here can be performed using that interface, but for some clients or servers, this interface may be easier to implement or work with. This specification may serve as a non-normative suggestion for HTTP operations on RDF graphs which are managed outside of a SPARQL 1.1 graph store.
This document describes an application protocol for the distributed updating and fetching of RDF graph content in a Graph Store via the mechanics of the Hypertext Transfer Protocol (HTTP) [RFC2616]. In doing so, it appeals to the following interface constraints that emphasize the core, architectural components underlying HTTP:
Servers implementing this protocol are HTTP/1.1 servers [RFC2616] and MUST interpret request messages as graph management operations on an underlying Graph Store. The subject of the operation is indicated by the request IRI.
This protocol specifies the semantics of HTTP operations for managing a Graph Store. In particular, it provides operations for removing, creating, and replacing RDF graph content as well as for adding RDF statements to existing RDF graph content. The interface defined here uses IRIs to direct native HTTP operations to an implementation of this protocol which responds by making appropriate modifications to the underlying Graph Store. A compliant implementation of this specification MUST accept HTTP requests directed at its Graph Store and handle them as specified by this protocol with the exception of security considerations such as those discussed in section 7 and others (Denial-of-Service attacks, etc.)
A client using this protocol to manipulate a graph store needs an IRI for each graph. Within the graph store, each graph (except the default graph) is associated with a graph IRI. In some cases ("Direct Graph Identification"), the graph IRIs can be directly used as the request URI of a graph management operation. In other cases ("Indirect Graph Identification"), the Graph Store IRI is used to route the operations onto RDF graph content.
We recall from [SPARQL] that IRIs for RDF graphs in SPARQL queries identify a resource, and the resource can have a representation that serializes that graph (or, more precisely: by an RDF document of the graph)
Per [RFC2616], the most common usage of a Request-URI is to identify a resource on an origin server or gateway. In our example, the corresponding request, -graphs/employees is meant to identify RDF triples on the example.com server that describe employees. In addition, the request specifies the GET method, which means that a representation of these triples should be returned. In this case, the preferred representation format is text/turtle
In this way, the server would route operations onto a named graph in a Graph Store via its Graph IRI. However, in using an IRI in this way, we are not directly identifying an RDF graph but rather the RDF graph content that is represented by an RDF document, which is a serialization of that graph. Intuitively, the set of interpretations that satisfy [RDF-MT] the RDF graph the RDF document serializes can be thought of as this RDF graph content.
The diagram illustrates this distinction. This diagram illustrates the basic kind of operation where the request URI identifies the RDF graph content being manipulated over the protocol. Requests to an implementation of this protocol receive HTTP requests using one of the HTTP methods that is directed at some RDF graph content. Above the arrows indicating the request is the relevant HTTP methods and below is any message body content or additional headers that accompany the request. At the head of the arrows leaving RDF graph content is the message body for the corresponding response.
As discussed in [RFC3986], query components are often used to carry identifying information in the form of key / value pairs where the value is another IRI. This protocol leverages this convention and provides a specific interface whereby a graph IRI can be embedded within the query component of the request IRI:
In the example above, the encoded graph IRI ( ) is percent-encoded [RFC3986] and indirectly identifies RDF triples to manipulate. Any server that implements this protocol and receives a request IRI in this form MUST perform the indicated operation on the RDF graph content identified by the IRI embedded in the query component where the IRI is the result of percent-decoding the value associated with the graph key. The query string IRI MUST be an absolute IRI and the server MUST respond with a 400 Bad Request if it is not. The diagram below illustrates this.
As indicated in section 3.3 of [RFC3986], the path component (of an IRI) contains data, usually organized in hierarchical form, that, along with data in the non-hierarchical query component, serves to identify a resource within the scope of the IRI's scheme and naming authority. As a result, the full request IRI identifies the same RDF graph content as does the IRI embedded in the query component.
In a similar manner, a query component comprised of the string default can be used to indicate that the operation indirectly identifies the default graph in the Graph Store. In this way, the example above can be modified to a request for an RDF/XML document that serializes the default graph in the Graph Store:
-graph-store identifies the Graph Store managed by the HTTP service. In order to dispatch requests to manage named or default graphs by embedding them in the query component of the Graph Store URL, the URL will need to be known a priori.
This section describes the use of the HTTP verbs to determine the operations performed on RDF graph content. In places where an equivalent SPARQL Update operation is given, is understood to be either the request IRI or the IRI indirectly specified via the query component as described above. Similarly, in the case of an operation that manages the default graph, the SPARQL Update operation will not include any mention of a graph.
This protocol also supports the proper handling of operations involving "multipart/form-data" [html4]. In particular, section 17.13.4 Form content types discusses how content indicated with the multipart/form-data content type are messages containing a series of parts. This protocol supports the submission of multiple RDF documents in operations involving some indicated RDF graph content via this mechanism, where each document is uploaded using the standard web form file upload widget. The specifics of this mechanism is discussed in section 5.5 (HTTP POST).
The user agent should attempt to supply a file name for each submitted file. The file name may be specified with the "filename" parameter of the 'Content-Disposition: form-data' header, or, in the case of multiple files, in a 'Content-Disposition: file' header of the subpart. Developers of implementations of this protocol should refer to [RFC2616] for additional details of appropriate behavior beyond those specified here. Section 5 only serves to define the behavior specific to the manipulation of RDF graph content. For example, conditional requests that make use of headers such as If-Modified-Since that are intended to reduce unnecessary network usage should be handled appropriately by implementations of this protocol per [RFC2616].
A request using an unsupported HTTP verb in conjunction with a malformed or unsupported request syntax MUST receive a response with a 405 Method Not Allowed. If the RDF graph content identified in the request does not exist in the server, and the operation requires that it does, a 404 Not Found response code MUST be provided in the response.
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