What is TRUE about Query Optimization?Select one:a. All of the aboveb.The cost of evaluating a query can vary depending on its type.c.The evaluation plan is built by the system, so the user need not focus on writing their query efficiently.d.An efficient query evaluation plan is generated by a database system, which minimizes its costs.
Question
What is TRUE about Query Optimization?Select one:a. All of the aboveb.The cost of evaluating a query can vary depending on its type.c.The evaluation plan is built by the system, so the user need not focus on writing their query efficiently.d.An efficient query evaluation plan is generated by a database system, which minimizes its costs.
Solution
The correct answer is: b. The cost of evaluating a query can vary depending on its type.
Step 1: Read the question and the options provided. Step 2: Understand the concept of query optimization. Step 3: Analyze each option and determine which one is true about query optimization. Step 4: Option a states "All of the above," but we need to verify if all the options are true. Step 5: Option b states that the cost of evaluating a query can vary depending on its type. This is a valid statement as the cost of evaluating a query can indeed vary based on factors such as the complexity of the query and the amount of data being processed. Step 6: Option c states that the evaluation plan is built by the system, so the user need not focus on writing their query efficiently. This statement is not necessarily true as the user can still optimize their query to improve performance. Step 7: Option d states that an efficient query evaluation plan is generated by a database system, which minimizes its costs. This statement is true as query optimization aims to generate an efficient evaluation plan that minimizes the cost of executing the query. Step 8: Based on the analysis, option b is the only true statement about query optimization. Step 9: Select option b as the correct answer.
Similar Questions
cost-based query optimization consist ofSelect one:a.Annotate resultant expressions to get alternative query plansb.All of the abovec.Generating logically equivalent expressions using equivalence rulesd.Choose the cheapest plan based on estimated cost
You are comparing two query execution plans.Query plan A has an estimated query cost of 1000Query plan B has an estimated query cost of 500What can we conclude from this?A.Query B will take 50% less time to execute than query AB.Query B is more efficient but that has no impact on query execution timeC.Query A is less efficient and most likely slower than a query B.
The activity of choosing an efficient execution strategy for processing a query is called asSelect one:a. Query plan evaluationb. Query executionc. Query parsingd. Query optimization
In Query optimization, Estimation of plan cost is based on:Select one:a.Statistics estimation for intermediate results to compute cost of complex expressionsb.All of the abovec.Cost formulae for algorithms, computed using statisticsd.Statistical information about relations
Which of the following is an important consideration when designing efficient database queries?Review LaterThe size of the databaseThe complexity of the database schemaThe number of tables in the databaseThe performance of the database server
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