In an ACID-compliant DBMS, a transaction that fails due to a disk crash fails du

Question

In an ACID-compliant DBMS, a transaction that fails due to a disk crash fails due to:

Durability

Consistency

Atomicity

Isolation

What is a major rule when using UNIONs?

All tables in the databases must have the same number of columns

You can only use two SELECT statements in a UNION

You can only union numeric data

The number of columns for each SELECT statement has to match

MySQL is:

Expensive

Not used in web development

Open source

Proprietary

Indexes should be placed on columns that:

Are queried frequently

Are updated often

Have a lot of unique values

All of the above

None of the above

Durability

Consistency

Atomicity

Isolation

What is a major rule when using UNIONs?

All tables in the databases must have the same number of columns

You can only use two SELECT statements in a UNION

You can only union numeric data

The number of columns for each SELECT statement has to match

MySQL is:

Expensive

Not used in web development

Open source

Proprietary

Indexes should be placed on columns that:

Are queried frequently

Are updated often

Have a lot of unique values

All of the above

None of the above

Six questions require you to derive the Astronoshow ERD into a relational model, this is one of them. Use the Astronoshow relation model to select which attributes would be present in the Astronomer relation. If Astronomer doesn't appear in the relational model choose 'None - Astronomer is not a relation in the relational model None - Astronomer is not a relation in the relational model First_Name Temperature O P.ID Last Name Location O Star Name Picture_Date iscovery Date O Coordinates A ID

Explanation / Answer

Q1. Attributes of Astronomer:

firstName, lastName, A_ID

Q2. In an ACID-compliant DBMS, a transaction that fails due to a disk crash fails due to:

Ans: Durability

Durability:

This property ensures that once the transaction has completed execution, the updates and modifications to the database are stored in and written to disk and they persist even is system failure occurs. These updates now become permanent and are stored in a non-volatile memory. The effects of the transaction, thus, are never lost.

Q3. What is a major rule when using UNIONs?

Ans: The number of columns for each SELECT statement has to match

Q4. MySQL is: Open source

Q5. Indexes should be placed on columns that:Are queried frequently

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.