QueryRunner can't return the meta data because it closes the ResultSet and
PreparedStatement objects after running the query. You can get access to
the meta data by implementing a ResultSetHandler and calling
rs.getMetaData() in the handle() method.
David
--- John Zoetebier <[EMAIL PROTECTED]> wrote:
> It would be helpful if QueryRunner would return ResultSetMetadata after
> running a query.
> I use ResultSetMetadata to dynamically build update and insert queries.
>
> At the moment I use the following class:
> ==>
> /*
> * Created on Dec 3, 2003
> *
> */
> package db;
>
> import java.sql.*;
> import java.util.ArrayList;
> import java.util.HashMap;
> import java.util.Iterator;
> import java.util.List;
> import java.util.Map;
> import java.util.logging.Logger;
>
> import util.Constants;
>
> /**
> *
> * @author johnz
> *
> */
> public final class TableMetaData {
>
> // Static variables
> // private static String catalog = "";
> // private static String schemaPattern = "APP";
> /**
> * Map with a list with meta data for each table
> * Each entry in list is a Map with column properties
> */
> private static Map tableMetaDataMap = new HashMap();
>
> private static final String[] columnPropertyNames = {
> "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. For char
> or date types this is
>
> the maximum number of characters, for numeric or decimal types this is
> precision.
> "BUFFER_LENGTH", // is not used.
> "DECIMAL_DIGITS", // int => the number of fractional
> digits
> "NUM_PREC_RADIX", // int => Radix (typically either 10 or 2)
> "NULLABLE", // int => is NULL allowed.
> // "columnNoNulls", - might not allow NULL values
> // "columnNullable", - definitely allows NULL values
> // "columnNullableUnknown", - nullability unknown
> "REMARKS", // String => comment
> describing column (may be null)
> "COLUMN_DEF", // String => default value (may be
> null)
> "SQL_DATA_TYPE", // int => unused
> "SQL_DATETIME_SUB", // int => unused
> "CHAR_OCTET_LENGTH", // int => for char types the maximum number of
> bytes in the column
> "ORDINAL_POSITION", // int => index of column in table (starting
> at 1)
> "IS_NULLABLE", // String => "NO" means column
> definitely does not
> allow NULL values; "YES" means the column might allow NULL values. An
> empty string means nobody knows.
> // "SCOPE_CATLOG", // String => catalog of table that is the
> scope of
> a
> reference attribute (null if DATA_TYPE isn't REF)
> // "SCOPE_SCHEMA", // String => schema of table that is the scope
> of a
>
> reference attribute (null if the DATA_TYPE isn't REF)
> // "SCOPE_TABLE", // String => table name that this the
> scope of a
> reference attribure (null if the DATA_TYPE isn't REF)
> // "SOURCE_DATA_TYPE" // short => source type of a distinct type or
> user-generated Ref type, SQL type from java.sql.Types (null if DATA_TYPE
>
> isn't DISTINCT or user-generated REF)
> };
>
>
>
> /**
> *
> */
> public TableMetaData() {
> super();
> }
>
> /**
> * Return list with meta data for selected table
> * Each entry in list is a map with column properties
> *
> * @see JavaDoc 1.4 java.sql.DatabaseMetaData.getColumns for name of
> the
> column properties
> * @param tableName
> * @return List of <code>Map</code> objects. Each map has entries with
> {ColumnProperty, PropertyValue}
> * @throws SQLException
> */
> public static List getTableMetaData(String tableName)
> throws SQLException {
>
> if (tableMetaDataMap.get(tableName) != null) {
> // MetaData have been chached
> return (List) tableMetaDataMap.get(tableName);
> }
>
> Logger log = Logger.getLogger("db");
> Connection conn = null;
> ResultSet rset = null;
> Statement stmt = null;
> DatabaseMetaData metaData = null;
> String msg = null;
>
> try {
> conn = DriverManager.getConnection(Constants.JDBC_URL);
> metaData = conn.getMetaData();
> rset = metaData.getColumns("", "APP", tableName, "%");
> List tableList = new ArrayList();
> Map columnPropertyMap;
> int i = 0;
> String columnPropterty = null;
> while (rset.next()) {
> // Create new map
> columnPropertyMap = new
> HashMap(columnPropertyNames.length);
>
> for (i = 0; i < columnPropertyNames.length; i++) {
> columnPropterty = columnPropertyNames[i];
> columnPropertyMap.put(columnPropterty,
> rset.getObject(columnPropterty));
> }
>
> tableList.add(columnPropertyMap);
> }
>
> tableMetaDataMap.put(tableName, tableList);
> return tableList;
> } catch (SQLException se) {
> msg = "SQL error: " + se.getMessage();
> log.warning(msg);
> throw new SQLException(msg);
> } finally {
> if (stmt != null) {
> stmt.close();
> }
> if (conn != null) {
> conn.close();
> }
> }
> }
>
> /**
> * Convenience method to get array of column properties for selected
> table
> * For name of column properties:
> * @see JavaDoc 1.4 java.sql.DatabaseMetaData.getColumns for name of
> the
> column properties
> * @param tableName
> * @param propertyName Name of property. For example to get all column
> names pass COLUMN_NAME
> * For list of all column properties see method getColumnProperties
> * @return List which enumerates the selected column property over all
> columns
> * @throws SQLException
> */
> public static List getTableColumnProperties(String tableName, String
> columnPropertyName)
> throws SQLException {
>
> List columnPropertyList = new ArrayList();
> List list = getTableMetaData(tableName);
> Map columnMap = null;
> Iterator iterator = list.iterator();
> int i = 0;
> Object obj = null;
>
> while (iterator.hasNext()) {
> columnMap = (Map) iterator.next();
> columnPropertyList.add(columnMap.get(columnPropertyName));
> }
> return columnPropertyList;
> }
>
> /**
> * Get array of all valid column properties
> *
> * @see JavaDoc 1.4 java.sql.DatabaseMetaData.getColumns for name of
> the
> column properties
> * Some properties not valid before SDK 1.4 are skipped
> * @return Array of column properties
> */
> public static String[] getColumnPropertyNames() {
>
> return columnPropertyNames;
> }
>
=== message truncated ===
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