This section describes how to get a list of all columns in a table or a view through the DatabaseMetaData object.
If you want list all columns in a table, you can use
the DatabaseMetaData method: getColumns(). Input parameters are:
catalog - a catalog name; must match the catalog name as it is stored in the database;
"" retrieves those without a catalog; null means that the catalog name should not be used to narrow the search
schemaPattern - a schema name pattern; must match the schema name as it is stored in the database;
"" retrieves those without a schema; null means that the schema name should not be used to narrow the search
tableNamePattern - a table name pattern; must match the table name as it is stored in the database
columnNamePattern - a column name pattern; must match the column name as it is stored in the database
The output is captured in a ResultSet object with
the following fields:
TABLE_CAT String => table catalog (may be null)
TABLE_SCHEM String => table schema (may be null)
TABLE_NAME String => table name
COLUMN_NAME String => column name
DATA_TYPE int => SQL type from java.sql.Types
TYPE_NAME String => Data source dependent type name, for a UDT the type name is fully qualified
COLUMN_SIZE int => column size.
DECIMAL_DIGITS int => the number of fractional digits. Null is returned for data types where DECIMAL_DIGITS is not applicable.
NULLABLE int => is NULL allowed.
The following sample program displays all columns in the Customer table:
/**
* ListColumns.java
* Copyright (c) 2007 by Dr. Herong Yang. All rights reserved.
*/
import java.sql.*;
public class ListColumns {
public static void main(String [] args) {
Connection con = null;
try {
Class.forName(
"com.microsoft.sqlserver.jdbc.SQLServerDriver");
con = DriverManager.getConnection(
"jdbc:sqlserver://localhost:1269;"
+ "user=sa;password=HerongYang;"
+ "database=AdventureWorksLT");
DatabaseMetaData meta = con.getMetaData();
ResultSet res = meta.getColumns(null, null, "Customer", null);
System.out.println("List of columns: ");
while (res.next()) {
System.out.println(
" "+res.getString("TABLE_SCHEM")
+ ", "+res.getString("TABLE_NAME")
+ ", "+res.getString("COLUMN_NAME")
+ ", "+res.getString("TYPE_NAME")
+ ", "+res.getInt("COLUMN_SIZE")
+ ", "+res.getString("NULLABLE"));
}
res.close();
con.close();
} catch (java.lang.ClassNotFoundException e) {
System.err.println("ClassNotFoundException: "
+e.getMessage());
} catch (SQLException e) {
System.err.println("SQLException: "
+e.getMessage());
}
}
}
