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Articles by Arushi
Page 6 of 9
Java ResultSet beforeFirst() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.The beforeFirst() method of the ResultSet interface moves the pointer of the current (ResultSet) object to the default position (before first), from the current position.Statement stmt = con.createStatement(); ResultSet rs = ...
Read MoreJava ResultSet afterLast() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.The afterLast() method of the ResultSet interface moves the pointer/cursor of the current ResultSet object to next position of the last row.rs.afterLast();Let us create a table with name MyPlayers in MySQL ...
Read MoreJava ResultSet wasNull() method with example
When we execute certain SQL queries (SELECT query in general) they return tabular data.The java.sql.ResultSet interface represents such tabular data returned by the SQL statements.i.e. the ResultSet object holds the tabular data returned by the methods that execute the statements which quires the database (executeQuery() method of the Statement interface in general).The ResultSet object has a cursor/pointer which points to the current row. Initially this cursor is positioned before first row.The wasNull() method of the ResultSet interface determines whether the last column read had a Null value. i.e. whenever you read the contents of a column of the ResultSet using the ...
Read MoreJava ResultSetMetaData getColumnType() method with example
The getColumnType() method of the ResultSetMetaData (interface) retrieves the type of the specified column in the current ResultSet object.This method accepts an integer value representing the index of a column and, returns an integer value representing the SQL type of the specified column.Following is the list of values returned by various datatypes of java.sql.Type −Array: 2003Big int: -5Binary: -2Bit: -7Blob: 2004Boolean: 16Char: 1Clob: 2005Date: 91Datalink70Decimal: 3Distinct: 2001Double: 8Float: 6Integer: 4JavaObject: 2000Long var char: -16Nchar: -15NClob: 2011Varchar: 12VarBinary: -3Tiny int: -6Time stamt with time zone: 2014Timestamp: 93Time: 92Struct: 2002SqlXml: 2009Smallint: 5Rowid: -8Refcursor: 2012Ref: 2006Real: 7Nvarchar: -9Numeric: 2Null: 0Smallint: 5To get the ResultSetMetaData ...
Read MoreJava ResultSetMetaData isAutoIncrement() method with example
The is AutoIncrement() method of the ResultSetMetaData (interface) determines whether a particular column in the current ResultSet object is automatically numbered.This method accepts an integer value representing the index of a column and, returns a boolean value which is −True, if the specified column is automatically numbered.False, if the specified column is not automatically numbered.To get the ResultSetMetaData object, you need to −Register the Driver: Select the required database register the Driver class of the particular database using the registerDriver() method of the DriverManager class or, the forName() method of the class named Class.DriverManager.registerDriver(new com.mysql.jdbc.Driver());Get connection: Create a connection object by ...
Read MoreJava DatabaseMetaData supportsBatchUpdates() method with example
The supportsBatchUpdates() method of the DatabaseMetaData interface is used to determine whether the underlying database supports batch updates.This method returns a boolean value which is −True, when the underlying database supports stored porcedures.False, when the underlying database doesn't support stored porcedures.To determine whether the underlying database supports stored porcedures −Make sure your database is up and running.Register the driver using the registerDriver() method of the DriverManager class. Pass an object of the driver class corresponding to the underlying database.Get the connection object using the getConnection() method of the DriverManager class. Pass the URL the database and, user name, password of ...
Read MoreJava DatabaseMetaData supportsTransactionIsolationLevel() method with example
JDBC provides support 5 transaction isolation levels through Connection interface.TRANSACTION_NONE: It is represented by integer value 0 does not support transactions.TRANSACTION_READ_COMMITTED: It is represented by integer value 2 supports transactions allowing Non-Repeatable Reads and, Phantom Reads.TRANSACTION_READ_UNCOMMITTED: It is represented by integer value 1 supports transactions allowing Dirty Reads, Non-Repeatable Reads and, Phantom Reads.TRANSACTION_REPEATABLE_READ: It is represented by integer value 4 supports transactions allowing only Phantom Reads.TRANSACTION_SERIALIZABLE: It is represented by integer value 8 supports transactions with out allowing Dirty Reads, Non-Repeatable Reads and, Phantom Reads.The supportsTransactionIsolationLevel() method of the DatabaseMetaData interface is used to determine whether the underlying database supports ...
Read MoreWhat are the transaction isolation levels supported by JDBC API?
JDBC provides support 5 transaction isolation levels through Connection interface.TRANSACTION_NONE: It is represented by integer value 0 does not support transactions.TRANSACTION_READ_COMMITTED: It is represented by integer value 2 supports transactions allowing Non-Repeatable Reads and, Phantom Reads.TRANSACTION_READ_UNCOMMITTED: It is represented by integer value 1 supports transactions allowing Dirty Reads, Non-Repeatable Reads and, Phantom Reads.TRANSACTION_REPEATABLE_READ: It is represented by integer value 4 supports transactions allowing only Phantom Reads.TRANSACTION_SERIALIZABLE: It is represented by integer value 8 supports transactions with out allowing Dirty Reads, Non-Repeatable Reads and, Phantom Reads.Following JDBC example displays all the transactions levels provided by the Connection interface of the JDBC ...
Read MoreJava DatabaseMetaData supportsUnion() method with example.
The SQL UNION clause/operator is used to combine the results of two or more SELECT statements without returning any duplicate rows.To use this UNION clause, each SELECT statement must haveThe same number of columns selectedThe same number of column expressionsThe same data type andHave them in the same orderBut they need not have to be in the same length.The basic syntax of a UNION clause is as follows −SyntaxSELECT column1 [, column2 ] FROM table1 [, table2 ] [WHERE condition] UNION SELECT column1 [, column2 ] FROM table1 [, table2 ] [WHERE condition]The supportsUnion() method of the DatabaseMetaData interface is used to ...
Read MoreWhat is ResultSet holdability in JDBC?
ResultSet holdability determines whether the ResultSet objects (cursors) should be closed or held open when a transaction (that contains the said cursor/ ResultSet object) is committed using the commit() method of the Connection interface.You can set the ResultSet holdability using the setHoldability() method of the Connection interface.con.setHoldability(ResultSet.CLOSE_CURSORS_AT_COMMIT);The ResultSet interface provides two values to specify the holdability of a ResultSet namely CLOSE_CURSORS_AT_COMMIT and, HOLD_CURSORS_OVER_COMMIT.Let us create a table with name MyPlayers in MySQL database using CREATE statement as shown below −CREATE TABLE MyPlayers( ID INT, First_Name VARCHAR(255), Last_Name VARCHAR(255), Date_Of_Birth date, Place_Of_Birth VARCHAR(255), Country VARCHAR(255), ...
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