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.
No comments:
Post a Comment