consistency

问题 I'm trying to check an ontology for its consistency. The ontology includes only descriptions of individuals, the class and semantic rules are described by an imported ontology. I thougt using the isConsistenct method would be the right choice. OWLReasonerFactory reasonerFactory = new StructuralReasonerFactory(); OWLReasoner reasoner = reasonerFactory.createNonBufferingReasoner(mergedOntology); if(reasoner.isConsistent()){ return "Merged ontology PASSED the consistency test"; }else{ return

问题 I have a question regarding the owlexplanation project by Matthew Horridge on GitHub. In the README file there is the following code : import org.semanticweb.owl.explanation.api.*; import org.semanticweb.owlapi.model.*; import org.semanticweb.owlapi.reasoner.OWLReasonerFactory; OWLReasonerFactory rf = ; // Get hold of a reasoner factory OWLOntology ont = ; // Reference to an OWLOntology // Create the explanation generator factory which uses reasoners provided by the specified // reasoner

问题 Lets say we have a order collection in firestore where each order needs to have a unique readable random order number with lets say 8 digits: { orderNumber: '19456734' } So for every incoming order we want to generate this unique number. What is the recommended approach in firestore to make sure no other document is using it? Note : One solution would be querying existing docs before saving, but this is not working in a concurrent scenario where multiple orders arrive at the same time (?).

问题 There is a point in Paxos algorithm (http://research.microsoft.com/en-us/um/people/lamport/pubs/paxos-simple.pdf) that I do not understand. It's about how to deal with the gaps, the paper describe two ways as below: The leader, as well as any other server that learns all the commands the leader knows, can now execute commands 1–135. However, it can’t execute commands 138–140, which it also knows, because commands 136 and 137 have yet to be chosen. T he leader could take the next two commands

问题 I know that Cassandra have different read consistency levels but I haven't seen a consistency level which allows as read data by key only from one node. I mean if we have a cluster with a replication factor of 3 then we will always ask all nodes when we read. Even if we choose a consistency level of one we will ask all nodes but wait for the first response from any node. That is why we will load not only one node when we read but 3 (4 with a coordinator node). I think we can't really improve

问题 I have to design the database for customers having prices for millions of materials they acquire through multiple suppliers for the next 24 months. So the database will store prices on a daily basis for every material supplied by a specific supplier for the next 24 months. Now I have multiple use cases to solve so I created multiple tables to solve each use case in the best possible way. Now the insertion of data into these tables will happen on a regular basis in a big chunk (let's say for

问题 I have to design the database for customers having prices for millions of materials they acquire through multiple suppliers for the next 24 months. So the database will store prices on a daily basis for every material supplied by a specific supplier for the next 24 months. Now I have multiple use cases to solve so I created multiple tables to solve each use case in the best possible way. Now the insertion of data into these tables will happen on a regular basis in a big chunk (let's say for

问题 This question already has answers here : Consistent pseudo-random numbers across platforms (6 answers) Closed 6 years ago . The title says it all, I am looking for something preferably stand-alone because I don't want to add more libraries. Performance should be good since I need it in a tight high-performance loop. I guess that will come at a cost of the degree of randomness. 回答1: Any particular pseudo-random number generation algorithm will behave like this. The problem with rand is that it

问题 I have a hierarchical structure stored in a table. Each element has a pointer to its previous, next and a parent create table CATALOGUE ( NAME VARCHAR2(300) not null, NEXT_ID NUMBER(38), PARENT_ID NUMBER(38), PREVIOUS_ID NUMBER(38), XID NUMBER(38) ); I have a java application, which uses O/R mapping to access and modify this table. Sometimes my catalog got corrupted, e.g. they are linked elements which don't have the same parent. I'm wondering if I can ensure data consistency using Oracle

问题 In an attempt to use Dynamodb for one of projects, I have a doubt regarding the strong consistency model of dynamodb. From the FAQs Strongly Consistent Reads — in addition to eventual consistency, Amazon DynamoDB also gives you the flexibility and control to request a strongly consistent read if your application, or an element of your application, requires it. A strongly consistent read returns a result that reflects all writes that received a successful response prior to the read. From the