Subjects such as JDBC require you to set your basics right in order to succeed in a job interview. Here are some of the most frequently asked JDBC questions that you can go through.
1. What do you understand by the database connection pooling? What are the advantages of using connection pooling?
As the name suggests, database connection pooling is defined as the process in which connections are chiefly stored in the cache so that they are reusable in the near future. So far as the merits are concerned, it is relatively quick and also helps evaluate the overall process of database pooling.
2. In JDBC, what do you understand by the term batch updates?
Batch update refers to the process of executing SQL queries concurrently. Barring select query, the method of batch updates may be applied to all other cases such as update, insert and delete.
3. What do you think are some the basic merits of using Prepared Statement in Java?
So far as the Prepared Statement is concerned, it is chiefly advantageous in that it helps iterative execution of the same SQL statements. Precisely, it is an important aspect of JDBC. However, it must be understood that the Prepared Statement is compiled not more than once.
4. Speaking of a prepared statement, why do you think it is quicker than direct execution?
Precisely, the prepared statement is faster because it is compiled only once. Apart from that, it is imperative to keep in mind that the prepared statement is directly connected with the JDBC driver so that there are no fundamental connection overheads. Consequently, the prepared statement is quicker than the execution of direct statements.
5. Can you tell us how many locking systems are there in the JDBC?
Essentially, there are two kinds of locking systems in the JDBC. Locking is an important aspect of the JDBC. Depending on the user situation, you decide whether to avail of the locking system. So there are two types: pessimistic locking and optimistic locking. Optimistic locking is used to lock a record only when you seek to update. On the other hand, pessimistic locking is used to lock the record from the select parameter in order to view and update.
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6. What do you understand by the term two phase commit?
So far as the two phase commit is concerned, it is chiefly used in the distribution transaction scheme. Specifically, the two phase commit is chiefly used to induce a degree of synchronization between several databases. Consequently, the two phase commit is one of the most vital and foundational aspects of JDBC.
7. Can you highlight the central reasons behind the occurrence of the No Suitable Driver error?
There could be many reasons for the same. For instance, it may be due to the occurrence of an invalid JDBC URL. Apart from that, it might also occur when the compiler is not able to load the JDBC drivers before invoking the getConncetion method. These are some of the most fundamental reasons behind the occurrence of this typical error.
8. What do you understand by the term metadata? Why do you think we need to use it?
Literally, metadata means data about data. Consequently, metadata is an essential tool to get info on other important data in order to retrieve an optimum database product vision, driver name and the number of tables and views. Precisely, metadata is one of the significant tools to be used in JDBC.
9. So far as Java is concerned, why is it imperative to close database connections?
Basically, the idea is to get over redundant exceptions in a particular program. For database closure, the resultset needs to be closed accompanied by the statement and connection.
10. What do you understand by JDBC save points?
JDBC save points represent those points which the present transaction may return to. Save point is useful in that it allows for a selective rollback of the transaction instead of inducing a blanket alteration, thus saving time and increasing code transparency. So save points are basic imperatives in JDBC.
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