2.14 DatabaseMetaData

2.14 DatabaseMetaData

-          (java.sql) Interface DatabaseMetaData :

-          public interface DatabaseMetaData

-          Comprehensive information about the database as a whole.

-          This interface is implemented by driver vendors.

-          To let users know the capabilities of a Database Management System (DBMS).

-          In combination with the driver based on JDBC technology ("JDBC driver").

-          That is used with it.

-          Different relational DBMSs often support different features, implement features in different ways, and use different data types.

-          In addition, a driver may implement a feature on top of what the DBMS offers.

-          Information returned by methods in this interface applies to the capabilities of a particular driver and a particular DBMS working together.

-          Note that as used in this documentation, the term "database" is used generically to refer to both the driver and DBMS.

-          A user for this interface is commonly a tool that needs to discover how to deal with the underlying DBMS.

-          This is especially true for applications that are intended to be used with more than one DBMS.

-          For example, a tool might use the method getTypeInfo to find out what data types can be used in a CREATE TABLE statement.

-          Or a user might call the method supportsCorrelatedSubqueries to see if it is possible to use a correlated subquery or supportsBatchUpdates to see if it is possible to use batch updates.

-          Some DatabaseMetaData methods return lists of information in the form of ResultSet objects.

-          Regular ResultSet methods, such as getString and getInt, can be used to retrieve the data from these ResultSet objects.

-          If a given form of metadata is not available, the ResultSet getter methods throw an SQLException.

-          Some DatabaseMetaData methods take arguments that are String patterns.

-          These arguments all have names such as fooPattern.

-          Within a pattern String, "%" means match any substring of 0 or more characters, and "_" means match any one character.

-          Only metadata entries matching the search pattern are returned.

-          If a search pattern argument is set to null, that argument's criterion will be dropped from the search.

-          A method that gets information about a feature that the driver does not support will throw an SQLException.

-          In the case of methods that return a ResultSet object, either a ResultSet object (which may be empty) is returned or an SQLException is thrown.