Online SPARQL Aggregate Queries Processing with Web …
Editors-in-Chief Krzysztof Janowicz. Managing Editor Cogan Shimizu Eva Blomqvist. Editorial Board Mehwish Alam Claudia d'Amato Stefano Borgo Boyan Brodaric
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Editors-in-Chief Krzysztof Janowicz. Managing Editor Cogan Shimizu Eva Blomqvist. Editorial Board Mehwish Alam Claudia d'Amato Stefano Borgo Boyan Brodaric
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GP can be discarded on push-down because the partial aggregation is the same as the total aggregation. Thus, as a special case of Rule 1 we obtain the following query equivalence: TG,H(".f(G)) = af(G)(%d (1) where G and H are the groupby and aggregate com- …
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An aggregate function is a function that performs a calculation on a set of values, and returns a single value. Aggregate functions are often used with the GROUP BY clause …
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Aggregate query processing has been studied in many research works [5]. But, as per our knowledge, not many of them consider communication cost in optimizing aggregate query processing. We analyzed some of the works which optimize the aggregate query operations. Along with that knowledge, we propose our storage
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Different forms of approximate queries (using domain-dependent notions of similarity) are already popular in many applications including data cleansing, pattern recognition, bioinformatics, address matching, and Internet search. Currently, the most popular approach for approximate query processing consists of a two-step (phase) process.
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The SQL Server Database Engine processes queries on various data storage architectures such as local tables, partitioned tables, and tables distributed across multiple …
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Data aggregation is any process in which information is gathered and expressed in a summary form, for purposes such as statistical analysis. A common aggregation purpose is to get more information about particular groups based on specific variables such as age, profession, or income. The information about such groups can then be used for Web ...
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According to the vertex attribute table, we can compute the result of this egocentric aggregate query is A V G (S a l a r y) = $206, 250. Mondal and Deshpande propose an aggregation overlay graph based index that shares pre-computed partial aggregate values among vertices w.r.t. a given aggregate function for egocentric …
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When specifying collation, the locale field is mandatory; all other collation fields are optional. For descriptions of the fields, see Collation Document.. If the collation is unspecified but the collection has a default collation (see db.createCollection()), the operation uses the collation specified for the collection.. If no collation is specified for the collection or for the …
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Read along to find out more. The core SQL aggregate functions are the following: COUNT(column_name | *) returns the number of rows in a table. SUM(column_name) returns the sum of the values of a numeric column. AVG(column_name) returns the average value of a numeric column. …
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Aggregate query processing. In this section, we consider aggregate queries with the SQL-syntax presented in Section 1. 3.1. The LCA algorithm: one-phase aggregation. A naive brute-force (BF) algorithm can be designed as follows. All sensor nodes take their readings periodically and keep these readings into their local tables.
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Log processing rules . Go to Settings > Log Monitoring > Processing to view log processing rules that are in effect, reorder the existing rules, and create new rules. Rules are executed in the order in which they're listed, from top to bottom. This order is critical because a preceding rule may impact the log data that a subsequent rule uses in its …
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Query Processing is the activity performed in extracting data from the database. In query processing, it takes various steps for fetching the data from the database. The steps involved are: Parsing and translation; Optimization; Evaluation; The query processing works in the following way: Parsing and Translation. As query processing includes ...
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Meanwhile, as one of the basic query operators, aggregate nearest neighbor (ANN) query retrieves a data entity whose aggregate distance, e.g. sum, max, to the given query data entities is smaller than those of other data entities in a database. ANN query on both certain graph data and high dimensional data has been well studied by previous work ...
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Online analytical processing (OLAP) is a core functionality in database systems. The performance of OLAP is crucial to make online decisions in many applications. However, it is rather costly to support OLAP on large datasets, especially big data, and the methods that compute exact answers cannot meet the high-performance …
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space for multi-granularity aggregate query process-ing, a novel approach is presented, which could de-creases the time overhead of query processing from O(m) to O(logm), where m is the number of win-dows being monitored. † An efficient synopsis, called Inverted Histogram (IH), is employed, and the algorithm for query processing is given.
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Therefore, query processing in data warehouse systems encompasses the definition, the logical and physical optimization, as well as the efficient execution of analytical queries. The specific techniques range from classic rewrite rules to rules considering the special structure of a query. For example, data warehouse queries usually target star ...
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The article includes an introduction to the approximate query processing concept, a definition of the available functions and their usage, and a generic test script …
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An aggregate function in SQL adds together multiple values and returns a single result. The aggregate function will carry out this calculation for each group of data when used with the GROUP BY clause. The GROUP BY statement is commonly used with aggregate functions ( MAX (), MIN (), SUM (), AVG (), COUNT () ) 3.
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Algebra (1) Query block: The basic unit that can be translated into the algebraic operators and optimized. A query block contains a single SELECT-FROM-WHERE expression, as well as GROUP BY and HAVING clause if these are part of the block. Nested queries within a query are identified as separate query blocks.
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aggregate: [adjective] formed by the collection of units or particles into a body, mass, or amount : collective: such as. clustered in a dense mass or head. formed from several separate ovaries of a single flower. composed of mineral crystals of one or more kinds or of mineral rock fragments. taking all units as a whole.
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The process of gathering and compiling data from various sources is known as data Aggregation. Businesses and groups gather enormous amounts of data from a variety of sources, including social …
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Data aggregation is the process of taking several rows of data and condensing them into a single result or summary. When dealing with large datasets, …
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An SQL aggregate function calculates on a set of values and returns a single value. For example, the average function ( AVG) takes a list of values and returns the average. …
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Definition. Aggregate queries generally take a set of objects as input and produce a single scalar value as output, summarizing one aspect of the set. Commonly used aggregate types include MIN, MAX, AVG, SUM, and COUNT. If the input set is very large, it might not be feasible to compute the aggregate precisely and in reasonable time.
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first proposed in [12]. Specifically, batch processing explo its the correlations between multiple queries, so that answering the batch as a whole can lead to higher overall accuracy than answering each query individually. For example, if one aggregate query Q1 (e.g., the total population of New York State and New Jersey) can be ex-
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The SQL aggregate functions — AVG, COUNT, DISTINCT, MAX, MIN, SUM — all return a value computed or derived from one column's values, after discarding any NULL values. The syntax of …
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Definition. Query processing denotes the compilation and execution of a query specification usually expressed in a declarative database query language such as the …
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SQL aggregate functions are pivotal in data analysis, allowing us to compute summary statistics from sets of rows. In this section, we delve into the core …
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The following table shows the most commonly used SQL Server aggregate functions: Calculate the average of non-NULL values in a set of values. Calculate a checksum value based on a group of rows. Return the number of rows in a group that satisfy a condition. Return the number of rows from a table, which meets a certain condition.
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To construct such a monotonic search space for multi-granularity aggregate query processing, a novel approach is presented, which could decreases the time overhead of query processing from O(m) to O(log m), where m is the number of windows being monitored. ... Definition 1 Assuming that F is an aggregate function, wli is the latest …
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Rapid query processing. SQL enables rapid query processing, enabling users to retrieve, manipulate or store data quickly and efficiently. However, optimizing queries for rapid processing involves a combination of proper indexing, query optimization and database design considerations. ... Data Definition Language commands are also called data ...
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