Q

QBE (Query By Example)

MarkLogic. QBE is a query whose structure closely models the structure of the documents you want to match. You can use a QBE to search XML and JSON documents with the REST and Java APIs.

QBFR (Query-Based Flexible Replication)

MarkLogic. Combining alerts (based on reverse queries that can trigger Flexible Replication of data) provides query-based flexible replication of your data. QBFR can be used in a pull or push scenario. See Configuring Alerting With Flexible Replication in Use Flexible Replication.

QName (Qualified name)

XML. A QName acts as a valid identifier for elements and attributes. A QName is composed of the namespace name and the local name. Together these uniquely define how the element or attribute is identified and are used to reference particular elements or attributes within XML documents. See also namespace.

QPS (queries per second)

MarkLogic. The number of query requests per second sent to the server.

quad

Semantics. A representation of a Subject, Predicate, Object, and an additional resource for the context of the triple. In MarkLogic, the fourth resource is taken to be a named graph.

query

MarkLogic. Any executable block of XQuery, SQL, or SPARQL. When you run a query in Query Console, you may view the results in your choice of formats.

Query Console

MarkLogic. Query Console is an interactive web-based query development tool for writing and executing ad-hoc queries in XQuery, JavaScript, SQL, SPARQL, and SPARQL Update. Query Console enables you to quickly test code snippets, debug problems, profile queries, and run administrative XQuery scripts. See Accessing Query Console in Use Query Console.

query roleset

Security. An association between one or more roles and one or more indexes for the purpose of determining privileges for concealed elements or properties using Element Level Security. See also protected path and query rolesets.

query rolesets

Security. The combination of query rolesets that apply to a path (XML) or property (JSON) in a document. See query roleset.

query statement

MarkLogic. A statement that contains no update calls. Query statements have a read-consistent view of the database. Since a query statement does not change the state of the database, the server optimizes it to hold no locks or lightweight locks, depending on the type of the containing transaction.

query transaction

MarkLogic. A transaction which cannot perform any updates; a read-only transaction. A transaction consisting of a single query statement in auto transaction mode, or any transaction created in query transaction mode. Attempting to perform an update in a query transaction raises XDMP-UPDATEFUNCTIONFROMQUERY. Instead of acquiring locks, query transactions run at a particular system timestamp and have a read-consistent view of the database.

quorum

The minimum number of hosts that must participate or give consent in a distributed operation for the operation to be considered valid or committed. In MarkLogic Server, a quorum is reached if more than 50% of the total number of hosts in a cluster-- excluding dynamic hosts--can communicate with one another. See Communication Between Nodes. [Updated for v12.0.0]