71 Advanced Java Tutorial | JDBC | DatabaseMetaData | Java Database Connectivity | adv java

Advanced Java Tutorial : adv java - #Metadata: (Data about the data is called as metadata). Java Database Connectivity

To know much details about the database software & its table, JDBC supports 3 modes metadata programming.

1) DatabaseMetaData
2) ResultSetMetaData
3) ParameterMetaData

1) DatabaseMetaData:
--------------------
- Gives limitatation & capability of underlaying Database software like database software name, version, more characters of table & etc...

- DatabaseMetaData object means its the object of a java class that implements java.sql.DatabaseMetaData.

-Call various methods on DatabaseMetaData object to gather much details about underlaying database software. (Here maximum methods are self descriptive.)

-to get the object of DatabaseMetaData-

DatabaseMetaData dbmd=con.getMetaData();


Example Java JDBC application to read MetaData of the Database.:
================================================================

import java.sql.*;

public class DatabaseMetaDataInfo
{
public static void main(String[] args) throws Exception
{
Class.forName("oracle.jdbc.driver.OracleDriver");
//sun.jdbc.odbc.JdbcOdbcDriver for type 1 driver
Connection con=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl", "scott", "boss");
//jdbc:odb:dsnname for type 1 driver


//get the DatabaseMetaData object
DatabaseMetaData dbmd=con.getMetaData();

System.out.println(" class that implements java.sql.DatabaseMetaData interface : "+dbmd.getClass().getName());

System.out.println(" database name :"+dbmd.getDatabaseProductName());

System.out.println("Database Version "+dbmd.getDatabaseProductVersion());

System.out.println("jdbc Driver Version "+dbmd.getDriverVersion());

System.out.println("sql keywords "+dbmd.getSQLKeywords());

System.out.println("Numeric Functions : "+dbmd.getNumericFunctions());

System.out.println("String functions :"+dbmd.getStringFunctions());

System.out.println(" System Functions :"+dbmd.getSystemFunctions());

System.out.println("Search String escape : "+dbmd.getSearchStringEscape());

System.out.println(" Supports stored procedures : "+dbmd.supportsStoredProcedures());

System.out.println("Maximum row size "+dbmd.getMaxRowSize());

System.out.println("Maximum statement length : "+dbmd.getMaxStatementLength());

System.out.println("max table in select query : "+dbmd.getMaxTablesInSelect());

System.out.println("max table name length :"+dbmd.getMaxTableNameLength());

System.out.println("Major jdbc API version : "+dbmd.getJDBCMajorVersion());

System.out.println("Minor jdbc API version : "+dbmd.getJDBCMinorVersion());

}
}

compile & run:



DatabaseMetadata programming is useful while developing GUI tools for dtabase software like sqlyog, mysqlfront , toadformsyql & etc...

-JDBC metadata programming is no where related to performing CURD (create, update, read, delete) operations on database.

its given to gather additional details about database software & tables.

- If certain JDBC driver can not retrive certain information about Dtabase then it returns 0 (zero) or null value while working with DatabaseMetaData.