What are types of JDBC drivers?
There are four types of
drivers defined by JDBC as follows:
- Type
1: JDBC/ODBC—These require an ODBC (Open Database Connectivity)
driver for the database to be installed. This type of driver works by
translating the submitted queries into equivalent ODBC queries and
forwards them via native API calls directly to the ODBC driver. It
provides no host redirection capability.
- Type2:
Native API (partly-Java driver)—This
type of driver uses a vendor-specific driver or database API to interact
with the database. An example of such an API is Oracle OCI (Oracle Call
Interface). It also provides no host redirection.
- Type
3: Open Protocol-Net—This is
not vendor specific and works by forwarding database requests to a remote
database source using a net server component. How the net server component
accesses the database is transparent to the client. The client driver
communicates with the net server using a database-independent protocol and
the net server translates this protocol into database calls. This type of
driver can access any database.
- Type
4: Proprietary Protocol-Net(pure Java driver)—This has a same
configuration as a type 3 driver but uses a wire protocol specific to a
particular vendor and hence can access only that vendor's database. Again
this is all transparent to the client.
Note: Type 4 JDBC driver is most preferred kind of approach
in JDBC.
Which type of JDBC driver is the fastest one?
JDBC Net pure Java driver(Type IV) is the fastest driver because it converts the
JDBC calls into vendor specific protocol calls and it directly interacts with
the database.
Does the JDBC-ODBC Bridge support
multiple concurrent open statements per connection?
No. You can open only one
Statement object per connection when you are using the JDBC-ODBC Bridge.
Which is the right type of
driver to use and when?
- Type I driver is
handy for prototyping
- Type III driver
adds security, caching, and connection control
- Type III and
Type IV drivers need no pre-installation
Note: Preferred by 9 out of 10 Java developers: Type IV. Click here to
learn more about JDBC drivers.
What are the standard isolation levels
defined by JDBC?
The values are defined in
the class java.sql.Connection and are:
- TRANSACTION_NONE
- TRANSACTION_READ_COMMITTED
- TRANSACTION_READ_UNCOMMITTED
- TRANSACTION_REPEATABLE_READ
- TRANSACTION_SERIALIZABLE
Any given database may
not support all of these levels.
What is resultset ?
The ResultSet
represents set of rows retrieved due to query execution.
ResultSet rs = stmt.executeQuery(sqlQuery);
What are the types of resultsets?
The values are defined in
the class java.sql.Connection and are:
- TYPE_FORWARD_ONLY specifies that a
resultset is not scrollable, that is, rows
within it can be advanced only in the forward direction.
- TYPE_SCROLL_INSENSITIVE specifies that a
resultset is scrollable in either direction but
is insensitive to changes committed by other transactions or other
statements in the same transaction.
- TYPE_SCROLL_SENSITIVE specifies that a
resultset is scrollable in either direction and
is affected by changes committed by other transactions or statements
within the same transaction.
Note: A TYPE_FORWARD_ONLY resultset is always insensitive.
What’s the difference between TYPE_SCROLL_INSENSITIVE and TYPE_SCROLL_SENSITIVE?
|
TYPE_SCROLL_INSENSITIVE |
TYPE_SCROLL_SENSITIVE |
|
An insensitive resultset
is like the snapshot of the data in the database when query was executed. |
A sensitive resultset does NOT
represent a snapshot of data, rather it contains
points to those rows which satisfy the query condition. |
|
After we get the resultset the
changes made to data are not visible through the resultset,
and hence they are known as insensitive. |
After we obtain the resultset if the
data is modified then such modifications are visible through resultset. |
|
Performance not effected with insensitive. |
Since a trip is made for every ‘get’ operation,
the performance drastically get affected. |
No comments:
Post a Comment