Câu hỏi gốc môn DBI202

524 câu gốc, sắp theo số đề từng chứa câu đó.

20 kết quả phù hợp nhất

What is a functional dependency?

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For the following relations and a Set operation: Employee | Name | City | Gender | | :--- | :--- | :--- | | Nguyen Trung Truc | HCM | Male | | Le Hong Son | HCM | Male | Customer | Name | City | Gender | | :--- | :--- | :--- | | Nguyen Trung Truc | HCM | Male | | Tran Tuyet Nhi | HN | Female | Employee \\ Customer What is the result of the Difference operation?

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Which of the following is correct?

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Your database contains a table named Purchases. The table includes a DATETIME column named PurchaseTime that stores the date and time each purchase is made. There is a non-clustered index on the PurchaseTime column. The business team wants a report that displays the total number of purchases made on the current day. You need to write a query that will return the correct results in the most efficient manner. Which Transact-SQL query should you use?

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The relation $R(A,B,C,D)$ has following FDs: $$\{AB \to C,\ ABD \to C,\ ABC \to D,\ AC \to D\}$$ Choose a correct statement about $R$?

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What is the hierarchical data model?

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What does the UNION operator on sets do?

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The _____ constraint is used to insert a default value into a column

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The IN SQL keyword

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When drawing an ERD: (a) Entity sets and their attributes should reflect reality (b) Redundancy is not important, so we can ignore it (c) Avoid introducing more elements into the design than is absolutely necessary (d) Choosing the right relationships

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What is the difference between Where and Having Clause?

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Here are two relations, R(A,B), S(C,D). (see figure): Table R: | A | B | |---|---| | 1 | 4 | | 2 | 5 | | 3 | 6 | | 4 | 7 | Table S: | C | D | |---|---| | 0 | 1 | | 1 | 0 | | 2 | 1 | Compute the result of the query: ```sql SELECT A, B, C, D FROM R LEFT OUTER JOIN S ON R.A = S.C ``` Identify, in the list below, the row that appears in the result.

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Let we examine the following code: ```sql DECLARE @a int; DECLARE @b int; PRINT @a + @b; ``` What is the output?

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Let R(A,B,C,D) with the following FDs: {AB->C, AC->B, AD->C} Choose a correct statement about R:

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If you wish to return a value from a stored procedure into a parameter, which of the following use?

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Which SQL keyword is used to sort the result-set?

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Look at the following statements: (a) For any relation schema, there is a dependency-preserving decomposition into 3NF. (b) For any relation schema, there is not a dependency-preserving decomposition into 3NF. (c) For any relation schema, there is a dependency-preserving decomposition into BCNF. (d) For some relation schema, there is not a dependency-preserving decomposition into BCNF.

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Why the intersection operator is not called a primitive relational algebra operator?

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Data Definition language (DDL) is used to .....

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A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Durable" mean?

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Câu hỏi gốc môn DBI202

What is a functional dependency?

Which of the following is correct?

The relation $R(A,B,C,D)$ has following FDs: $$\{AB \to C,\ ABD \to C,\ ABC \to D,\ AC \to D\}$$ Choose a correct statement about $R$?

What is the hierarchical data model?

What does the UNION operator on sets do?

The _____ constraint is used to insert a default value into a column

The IN SQL keyword

When drawing an ERD: (a) Entity sets and their attributes should reflect reality (b) Redundancy is not important, so we can ignore it (c) Avoid introducing more elements into the design than is absolutely necessary (d) Choosing the right relationships

What is the difference between Where and Having Clause?

Let we examine the following code: ```sql DECLARE @a int; DECLARE @b int; PRINT @a + @b; ``` What is the output?

Let R(A,B,C,D) with the following FDs: {AB->C, AC->B, AD->C} Choose a correct statement about R:

If you wish to return a value from a stored procedure into a parameter, which of the following use?

Which SQL keyword is used to sort the result-set?

Why the intersection operator is not called a primitive relational algebra operator?

Data Definition language (DDL) is used to .....

A database transaction, by definition, must be ACID (atomic, consistent, isolated and durable). What does "Durable" mean?