Retrieving Tables from a Database
In database system it is very important to know about
the tables. To work with this, it is very important to know how to retrieve a table and
create a table in the database. This section provides you a facility for retrieving
tables from a specific database through an example. In relational database,
all the data is stored in the tabular format (rows and columns). See detail
information below:
Description of program:
In this program we are establishing the connection
between the MySQL
database and Java file. We will retrieve the table with the help of
some java methods and APIs interface. If the database has one or more tables then
it shows all tables, otherwise displays the message "No any table in the
database".
Description of code:
DatabaseMetaData:
This is an interface of java.sql package that implemented by
driver vendors. It tells about the data of the data like number of tables in the
database , the information about the columns of the table.
getMetaData():
It is a method of Connection interface. This method has metadata around the database and retrieves DatabaseMetaData
object.
ResultSet:
The ResultSet is an interface that provides getter methods (getBoolean,
getString, getTable and so on) for retrieving values. A ResultSet object
is by default not updatable and forward only.
getTables(null, null, "%", types):
This method returns ResultSet and takes the following
string types parameter:
catalog : Table catalog name
(may be null)
schemaPattern : Table catalog
name (may be null)
tableNamePattern : Table
name("%")
types : Table type
rs.next():
This method returns the next element of the ResultSet object.
getString("Table name"):
Above method retrieves the values from ResultSet object. It takes
string type value.
Here is the code of program:
import java.sql.*;
public class AllTableName{
public static void main(String[] args) {
System.out.println("Listing all table name in Database!");
Connection con = null;
String url = "jdbc:mysql://localhost:3306/";
String db = "jdbctutorial";
String driver = "com.mysql.jdbc.Driver";
String user = "root";
String pass = "root";
try{
Class.forName(driver);
con = DriverManager.getConnection(url+db, user, pass);
try{
DatabaseMetaData dbm = con.getMetaData();
String[] types = {"TABLE"};
ResultSet rs = dbm.getTables(null,null,"%",types);
System.out.println("Table name:");
while (rs.next()){
String table = rs.getString("TABLE_NAME");
System.out.println(table);
con.close();
}
}
catch (SQLException s){
System.out.println("No any table in the database");
}
}
catch (Exception e){
e.printStackTrace();
}
}
}
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Output of program:
C:\vinod\jdbc\jdbc-mysql>javac AllTableName.java
C:\vinod\jdbc\jdbc-mysql>java AllTableName
Listing all table name in Database!
Table name:
employee
employee11
employee2
employee3
employee4
employee5
employee6
employee8
employee9
java_datatypes
java_datatypes2
javatypes
|
Download this
example.
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