Term
What is automatic dirty checking?
(not necessary) |
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Definition
| At the end of every transaction, Hibernate automatically persists back to the database all objects that have been modified in the transaction. |
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Term
What is transactional write-behind?
(not necessary) |
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Definition
When Hibernate collects all database operations associated with a transaction, it creates a minimum set of SQL queries and executes them.
transaction.commit(); |
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Term
What is the use of dynamic-insert attributes in a class mapping?
(not necessary) |
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Definition
| Specifies that INSERT SQL should be generated at runtime and contain only the columns whose values have changed. |
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Term
What is the use of dynamic-update attributes in a class mapping?
(not necessary) |
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Definition
Specifies that UPDATE SQL should be generated at runtime and contain only those columns whose values have changed.
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Term
What are the ways to express joins in HQL?
(Hint: 4)(not necessary) |
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Definition
- An implicit association join.
- An ordinary join in the FROM clause.
- A fetch join in the FROM clause.
- A theta-style join in the WHERE clause. |
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Term
Explain named SQL query.
(not necessary) |
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Definition
| It is a way to map a name to a query that might be called several times in your code at different places. |
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Term
What is the difference between sorted and ordered collections in hibernate?
(not necessary) |
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Definition
- Sort collection – sorted by features provided by the Java collections framework. Works on small collections.
- Order collection – sorted by specifying the order-by clause when it is retrieved. Works on large collections.
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Term
What are the ORM levels?
(Hint: 4)(not necessary) |
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Definition
a. Pure relational (stored procedure).
b. Light object mapping (JDBC)
c. Medium object mapping.
d. Full object Mapping (composition, inheritance, polymorphism, persistence by reach-ability) |
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Term
What is the difference between and merge and update?
(not necessary) |
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Definition
- Update() should be used to save the data when the session does not contain an already persistent instance with the same identifier.
- Merge() should be used if you want to save your modifications at any time without knowing the state of a session.
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Term
Define cascade and inverse in one-many mapping?
(not necessary) |
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Definition
Cascade() - Enables operations to cascade to child entities.
Inverse() - Indicates which end of a relationship should be ignored.
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