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Page 564 of 589
How to group queries using transaction in a JSP?
The tag is used to group the and tags into transactions. You can put as many and tags as statements inside the tag to create a single transaction.It ensures that the database modifications performed by the nested actions are either committed or rolled back if an exception is thrown by any nested action.AttributeThe tag has the following attributes −AttributeDescriptionRequiredDefaultdataSourceDatabase connection to use (overrides the default)NoDefault databaseisolationTransaction isolation (READ_COMMITTED, READ_UNCOMMITTED, REPEATABLE_READ, or SERIALIZABLE)NoDatabase’s defaultExampleTo start with the basic concept, let us create a Students table in the TEST database and create a few records ...
Read MoreHow to process SQL statements with JDBC explain with an example?
To process an SQL statement, you need to follow the steps given below:Establish the connection.Create a statement.Execute the statement/query.Process the result.Close the connection.Establishing a ConnectionTo process SQL statements first of all you need to establish connection with the desired DBMS or, file System or, other data sources.To do so, Register the JDBC driver class, corresponding to the DataSource you need to the DriverManager using the registerDriver() method.Driver myDriver = new com.mysql.jdbc.Driver(); DriverManager.registerDriver(myDriver);This method accepts an object of the Driver class; it registers the specified Driver with the DriverManager.You can also register the driver using the forName() method. This method loads ...
Read MoreWhat is Type_FORWARD_ONLY ResultSet in JDBC?
A ResultSet interface in JDBC represents the tabular data generated by SQL queries. It has a cursor which points to the current row. Initially, this cursor is positioned before the first row.You can retrieve the column value at the current row using the getter methods getInt(), getString(), getDate() etc…To move the cursor and to navigate/iterate through the ResultSet the java.sql.ResultSet interface provides various methods such as next(), Previous(), first(), last(), relative(), absolute(), beforeFirst(), afterLast() etc...Type_FORWARD_ONLY Only ResultSetIn forward only ResultSet you can move the cursor only in forward direction. By default, a ResultSet is of type forward only.
Read MoreCan we test XPath expression in JSP?
The tag evaluates a test XPath expression and if it is true, it processes its body. If the test condition is false, the body is ignored.AttributeThe tag has the following attributes −AttributeDescriptionRequiredDefaultselectThe XPath expression to be evaluatedYesNonevarName of the variable to store the condition's resultNoNonescopeScope of the variable specified in the var attributeNoPageExampleFollowing is an example that show the use of the tag − JSTL x:if Tags Books Info: ...
Read MoreWhat is TYPE_SCROLL_INSENSITIVE ResultSet in JDBC?
This represents a scrollable ResultSet i.e. the cursor moves in forward or backward directions. This type of ResultSet is insensitive to the changes that are made in the database i.e. the modifications done in the database are not reflected in the ResultSet.Which means if we have established a connection with a database using JDBC program and retrieved a ResultSet holding all the records in a table named SampleTable and, meanwhile if we add some more records to the table (after retrieving getting the ResultSet), these recent changes will not be reflected in the ResultSet object we previously obtained.ExampleConsider we have ...
Read MoreCan we have a switch statement in JSP for XPath expression?
The tag works like a Java switch statement. With this, you can choose between a number of alternatives. Where the switch statement has the case statements, the tag has the tags. In a similar way, a switch statement has the default clause to specify a default action and the tag has the tag as the default clause.AttributeThe tag does not have any attribute.The tag has one attributes which is listed below.The tag does not have any attribute.The tag has the following attributes −AttributeDescriptionRequiredDefaultselectCondition to evaluateYesNoneExample ...
Read MoreWhat is TYPE_SCROLL_SENSITIVE ResultSet in JDBC?
This represents is a scrollable ResultSet i.e. the cursor moves in forward or backward directions. This type of ResultSet is sensitive to the changes that are made in the database i.e. the modifications done in the database are reflected in the ResultSet.Which means if we have established a connection with a database using a JDBC program and retrieved a ResultSet holding all the records in a table named SampleTable. Meanwhile, if we have added some more records to the table (after retrieving the ResultSet), these recent changes will be reflected in the ResultSet object we previously obtained.Following is an example ...
Read MoreWhat is the difference between the TYPE_SCROLL_INSENSITIVE and TYPE_SCROLL_SENSITIVE ResultSets in JDBC?
In the TYPE_SCROLL_INSENSITIVE ResultSet, the cursor moves in forward or backward directions. This type of ResultSet is insensitive to the changes that are made in the database i.e. the modifications done in the database are not reflected in the ResultSet.Which means if we have established a connection with a database using a JDBC program and retrieved a ResultSet holding all the records in a table named SampleTable. Meanwhile, if we have added some more records to the table (after retrieving getting the ResultSet), these recent changes will not be reflected in the ResultSet object we previously obtained.In the TYPE_SCROLL_SENSITIVE ResultSet, ...
Read MoreWhat is ResultSet Concurrency in JDBC?
The concurrency of the ResultSet object determines whether its contents can be updated or not.The Connection interface provides 3 variants of the createStatement() method where one of the method's signature is as follows:Statement createStatement(int resultSetType, int resultSetConcurrency)This method accepts two integer type variables where one represents the type of the ResultSet and the other represents the Concurrency of the ResultSet.The ResultSet interface provides two values to specify the concurrency of the ResultSet.CONCUR_READ_ONLY: If you set this as a value of the concurrency while creating the ResultSet object you cannot update the contents of the ResultSet you can only read/retrieve them.CONCUR_UPDATABLE: ...
Read MoreWhat is CONCUR_READ_ONLY ResultSet in JDBC? Explain?
In general, you will pass this as a value to the createStatement() method as a value of ResultSet Concurrency type.Statement createStatement(int resultSetType, int resultSetConcurrency)This type of result set is not updatable. i.e. once you get a ResultSet object you cannot update its contents.ExampleSuppose, we have a table named Employee in the database with the following contents:+----+---------+--------+----------------+ | Id | Name | Salary | Location | +----+---------+--------+----------------+ | 1 | Amit | 3000 | Hyderabad | | 2 | Kalyan | 4000 | Vishakhapatnam | | 3 | Renuka | 6000 ...
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