Java Reference
In-Depth Information
The most noticeable effects of modifying the example to handle different RDBMS systems and different
drivers are how minimal the required changes are and how pronounced a difference it makes to use the
Opta2000 driver instead of the jdbc:odbc bridge in terms of speed.
Using DatabaseMetaData
The DatabaseMetaData interface provides the following types of information about the database:
 
General information about the data source, including:
 
Database product name and version
 
Driver name
 
Database URL
 
Feature support, such as:
 
SQL92 Support level
 
SQL keywords recognized
 
Transaction Isolation levels supported
 
Support of features such as batch updates
 
Data-source limits including:
 
The maximum number of columns in a table
 
The maximum lengths of column and table names
 
Information about the SQL objects the source contains, such as:
 
The types of tables in a catalog
 
The names of all tables of each type
 
Information about all columns in the tables
Many of the DatabaseMetaData methods return information in ResultSets , allowing you to use
ResultSet methods such as getString() and getInt() to retrieve this information. If a given form
of metadata is not available, these methods throw a SQLException. The next section illustrates how to
retrieve information about the database.
Retrieving Information about the Database
Figure 10-2 illustrates the kind of information you can get about a database using the
DatabaseMetaData object. The JTree displays the types of tables in the database, with the table
names of each type of table displayed as child nodes of the table type. Tables can be expanded to
display column names, and the columns themselves can be expanded to show information about the
column.
Figure 10-2: Tree view of tables in a database
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