Has a number of different meanings, used to indicate partition elimination, may also indicate an actual filter step where one row source is filtering, another, functions such as min may introduce filter steps into query plans. 3.view --视图,大都由内联视图产生(可能深入到视图基表) When a view...
Method for looking up a single key value via a unique index. always returns a single value, You must supply AT LEAST the leading column of the index to access data via the index. index range scan --索引局部扫描 Index range scan is a method for accessing a range values of a particular ...
DbVisualizer presents the plan either in a tree style format or in a graph, or in a simple text format. What information is shown depends on the database you use. In the tree view, put the mouse pointer on the column header for a tooltip description what that column represents. The fol...
2) Explain why functions with an array parameter are usually complemented with an additional integer parameter (reference specifics in this workshop to explain your answer). Explain what does the following function do: void foo(Queue *q, Stack *s) { while (!q->isEmpty() { s->push(q->...
Describe the functions provided by a relational database that could be used to record courses taken by university students in order to manage scheduling and preparing transcripts. What function does an attribute of an entity perform in a DBMS?...
(AWR) SQL Tuning Set (STS) SQL Plan Baseline (SPM) Using the EXPLAIN PLAN Command and the DBMS_XPLAN.DISPLAY Function The following examples illustrate how to generate and display an execution plan for our original SQL statement using the different functions provided in the DBMS_...
SQL Performance : Guideline for Tuning the SQL Queries in Oracle RDBMS DBMS is a complex system that is composed of a collection of subsystems, each with a specific task and will interact with the user application programs and the database. Maintaining DBMS performance is a challenging task. ...
#5. Name and describe the two main categories of BI systems. #6. What are the three sources of data for BI systems? #7. Explain the difference in processing between reporting and data mining applications. #8. What is an ETL system, and ...
In this paper we’ll discuss an overview of the EXPLAIN PLAN and TKPROF functions built into the Oracle 8i server and learn how developers and DBAs use these tools to get the best performance out of their applications. We’ll look at how to invoke these tools both from the command line ...
Describe at least three functions that a Database Management System (DBMS) performs to help create an accurate and consistent view of data throughout an enterprise. Describe which of the seven primary product or process impacts of LCA you believe presents the grea...