What is a top K query?
The top-k query is define as- Given a database D of m objects, each of which is characterized by n attributes, a scoring function f, according to which we rank the objects in D, and the number of expected results k. Then a top-k query Q returns the k objects with the highest rank in f.
What is query processing in data mining?
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.
Which query processing method is more efficient?
Pipelining vs. Materialization
Pipelining | Materialization |
---|---|
It is a more efficient way of query evaluation as it quickly generates the results. | It is less efficient as it takes time to generate the query results. |
What is relational query processing?
Definition. Query processing denotes the compilation and execution of a query specification usually expressed in a declarative database query language such as the structured query language (SQL). Query processing consists of a compile-time phase and a runtime phase.
What are the steps in query processing?
For our case, let us consider the SQL query written above.
- Step 1: Parsing.
- Step 2: Translation.
- Step 3: Optimizer.
- Step 4: Execution Plan.
- Step 5: Evaluation.
What is query processing explain with example?
Query Processing is a translation of high-level queries into low-level expression. It is a step wise process that can be used at the physical level of the file system, query optimization and actual execution of the query to get the result. It requires the basic concepts of relational algebra and file structure.
How many stages are in query processing?
There are four phases in a typical Query Processing in DBMS.
What are the different steps of query processing?
For our case, let us consider the SQL query written above.
- Step 1: Parsing.
- Step 2: Translation.
- Step 3: Optimizer.
- Step 4: Execution Plan.
- Step 5: Evaluation.
What is query processing steps?
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.
https://www.youtube.com/watch?v=5jYD_sGQQR8