Câu hỏi gốc môn DBI202

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

20 kết quả phù hợp nhất

A ______ is a collection of programs that enables user to create and maintain databases. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the databases for various applications

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There is an auction database consists the following tables: ```sql Member(memberID, memberName) Auction_item(itemID, itemName, sellerID, endTime) Bid(itemID, bidderID, bidPrice) ``` All registered members can put up item to sell (stored in auction_item table), and can bid repeatedly one item (stored in bid table). Current price of an item is maximum bidPrice. Which of the following SQL statement show the current price for each item?

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What type of key is used to reference another table?

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The most widely used conceptual model is the ____ model.

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Every row and value must agree with all constraints right after the transaction is complete. The above describes which property of a transaction?

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The ER Diagram uses three principle element types:

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A set of attributes forms a _____ for a relation if we do not allow 2-tuples in a relation instance to have the same values in all that attributes

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Suppose R is a relation with attributes A1, A2, A3, A4. The only key of R is A1. So, how many super-keys does R have?

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Choose one correct statement:

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Suppose that tuple $t$ appears, respectively, $x$, $y$, and $z$ times in the relations $X$, $Y$, and $Z$. Let $t$ appear $w$ times in the relation: $X \cup (Y \cap Z)$ Which of the following inequalities is true?

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Alison wants to make sure that her query plan is guaranteed to be up to date when executing a stored procedure. She does not mind if it takes longer to execute that stored procedure. How can she ensure this?

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Choose the correct statements.

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What is the goal of decomposition when designing a database?

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Here are three relations, $R(A,B)$, $S(C,D)$, and $T(E,F)$. | A | B | | :--- | :--- | | 0 | 1 | | 1 | 0 | | 1 | 1 | | C | D | | :--- | :--- | | 0 | 1 | | 1 | 0 | | 1 | 1 | | E | F | | :--- | :--- | | 0 | 1 | | 1 | 0 | | 1 | 1 | Compute the result of the query: ```sql SELECT A, F, SUM(C), SUM(D) FROM R, S, T WHERE B = C AND D = E GROUP BY A, F HAVING COUNT(*) > 1 ```

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Database integrity ensures that:

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What does ACID stand for?

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How to eliminate anomalies when we design a database?

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When join R and S, we want to display all the records in R we must use:

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Consider the law, that holds for set relations: $(S \cap T) - R = S \cap (T - R)$ The above law still hold for bag relations?

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The relation $R(A,B,C,D)$ has following FDs: $ACD \to B$; $AC \to D$; $D \to C$; $AC \to B$. Choose the correct statement about $R$:

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Câu hỏi gốc môn DBI202

A ______ is a collection of programs that enables user to create and maintain databases. In other words, it is general-purpose software that provides the users with the processes of defining, constructing and manipulating the databases for various applications

What type of key is used to reference another table?

The most widely used conceptual model is the ____ model.

Every row and value must agree with all constraints right after the transaction is complete. The above describes which property of a transaction?

The ER Diagram uses three principle element types:

A set of attributes forms a _____ for a relation if we do not allow 2-tuples in a relation instance to have the same values in all that attributes

Suppose R is a relation with attributes A1, A2, A3, A4. The only key of R is A1. So, how many super-keys does R have?

Choose one correct statement:

Suppose that tuple $t$ appears, respectively, $x$, $y$, and $z$ times in the relations $X$, $Y$, and $Z$. Let $t$ appear $w$ times in the relation: $X \cup (Y \cap Z)$ Which of the following inequalities is true?

Alison wants to make sure that her query plan is guaranteed to be up to date when executing a stored procedure. She does not mind if it takes longer to execute that stored procedure. How can she ensure this?

Choose the correct statements.

What is the goal of decomposition when designing a database?

Database integrity ensures that:

What does ACID stand for?

How to eliminate anomalies when we design a database?

When join R and S, we want to display all the records in R we must use:

Consider the law, that holds for set relations: $(S \cap T) - R = S \cap (T - R)$ The above law still hold for bag relations?

The relation $R(A,B,C,D)$ has following FDs: $ACD \to B$; $AC \to D$; $D \to C$; $AC \to B$. Choose the correct statement about $R$: