query


Also found in: Dictionary, Thesaurus, Medical, Legal, Financial, Acronyms, Wikipedia.
Related to query: Database query

query

[′kwir·ē]
(computer science)
A computer instruction to interrogate a data base.

query

(database, information science)
A user's (or agent's) request for information, generally as a formal request to a database or search engine.

SQL is the most common database query language.

query

(character)

query

To search for data. In addition to obtaining lists of records that match the search criteria, queries to a database allow for counting items and summing amounts. A query to a search engine such as Google or Bing yields a summary of the contents of Web pages and is more often called a "search."

For years, query and report programs have been the primary applications that produce output from information systems. A query implies an online request as required (look up that record), while a report implies a more elaborate printout with page headings and numbers that is typically produced at regular intervals such as end of month. See report writer.

Simple or Complex
Defining a query for a relational database can be extremely simple or very complex. If the query is based on one matching condition, such as "retrieve all customers who owe us more than $10,000," it is usually easy to define in a query language or program. However, "retrieve all customers who owe us more than $10,000 from purchasing toasters" is not easy. It requires several steps to determine how many toaster orders are in the balance due.

Tables Must Be Joined
Relational databases are designed to eliminate redundancy. The goal is to store a data item in one table and not have it duplicated in others. For example, an order record will contain the product number ordered, but often not its description. The description is stored in a product table. Thus, any printout of products ordered and their descriptions requires that the order table be linked to the product table for that query or report. Linking customer, order and product tables is a common example of "joining" tables to satisfy a query.

Contents of a Query
Most queries require at least the following conditions to be stated. First, which table or tables is the data coming from. If from two or more tables, what is the link between (typically account number or name). Next, define the selection criteria, which is the matching condition or filter. Lastly, define which fields in the tables are to be displayed or printed in the result. See SQL.


The Query Statement
This diagram depicts the typical conditions that have to be stated when querying a relational database.
References in periodicals archive ?
The spatio-temporal query processing module provides a temporal relation operator to support temporal operation processing, as shown in Table 2.
13) provides a spatio-temporal analysis operator by extending standard structured query language (SQL) specification released by the Open Geospatial Consortium (OGC).
In Section 3, basic concepts such as query processing and materialized views on XML documents are introduced.
As mentioned in Section 1, one research direction on querying XML documents was to build materialized views on XML documents to reduce the number of visited nodes during tree traversing, thereby leading to faster query processing.
In unintended networks [3], to get only the required information items effectively every mobile node retrieves information items employing a top-k query. so as to scale back the traffic with high accuracy of the query result, every node can send a bar graph information [4] supported the query to query provision node with this bar graph it's straightforward to search out the best score value.
In contrast, in the ranking step, the most simple and straightforward ranking approach is based on query's past popularity, which is referred to as the Most Popular Completion (MPC) model [2]:
If the query point is contained in n, you need to do from top to bottom and sub tree traversal search.
Switch to Datasheet view for one last look at the data that will be added when the query is run.
In this research, we propose an aspect-based query expansion technique to diversify the retrieved documents for the original query.
Section 2 gives the related work and the previous proposed techniques for data query. In Section 3, we describe the system model and the security model.
For any enterprise one can discern a number of query types related to different tasks.
To find these, use the query "is:important." And if you add "is:unread" in the query, you get the list of important unread mails.