libjava/classpath/java/sql/ResultSetMetaData.java

   1 /* ResultSetMetaData.java -- Returns information about the ResultSet
   2    Copyright (C) 1999, 2000, 2002, 2006 Free Software Foundation, Inc.
   3
   4 This file is part of GNU Classpath.
   5
   6 GNU Classpath is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 2, or (at your option)
   9 any later version.
  10
  11 GNU Classpath is distributed in the hope that it will be useful, but
  12 WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14 General Public License for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GNU Classpath; see the file COPYING.  If not, write to the
  18 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  19 02110-1301 USA.
  20
  21 Linking this library statically or dynamically with other modules is
  22 making a combined work based on this library.  Thus, the terms and
  23 conditions of the GNU General Public License cover the whole
  24 combination.
  25
  26 As a special exception, the copyright holders of this library give you
  27 permission to link this library with independent modules to produce an
  28 executable, regardless of the license terms of these independent
  29 modules, and to copy and distribute the resulting executable under
  30 terms of your choice, provided that you also meet, for each linked
  31 independent module, the terms and conditions of the license of that
  32 module.  An independent module is a module which is not derived from
  33 or based on this library.  If you modify this library, you may extend
  34 this exception to your version of the library, but you are not
  35 obligated to do so.  If you do not wish to do so, delete this
  36 exception statement from your version. */
  37
  38
  39 package java.sql;
  40
  41 /**
  42  * This interface provides a mechanism for obtaining information about
  43  * the columns that are present in a <code>ResultSet</code>.
  44  *
  45  * <p> Note that in this class column indices start at 1, not 0.</p>
  46  *
  47  * @author Aaron M. Renn (arenn@urbanophile.com)
  48  */
  49 public interface ResultSetMetaData
  50 {
  51   /**
  52    * The column does not allow NULL's.
  53    */
  54   int columnNoNulls = 0;
  55
  56   /**
  57    * The column allows NULL's.
  58    */
  59   int columnNullable = 1;
  60
  61   /**
  62    * It is unknown whether or not the column allows NULL's.
  63    */
  64   int columnNullableUnknown = 2;
  65
  66   /**
  67    * This method returns the number of columns in the result set.
  68    *
  69    * @return The number of columns in the result set.
  70    * @exception SQLException If an error occurs.
  71    */
  72   int getColumnCount() throws SQLException;
  73
  74   /**
  75    * This method test whether or not the column is an auto-increment column.
  76    * Auto-increment columns are read-only.
  77    *
  78    * @param columnIndex The index of the column to test.
  79    * @return <code>true</code> if the column is auto-increment, <code>false</code>
  80    *         otherwise.
  81    * @exception SQLException If an error occurs.
  82    */
  83   boolean isAutoIncrement(int columnIndex) throws SQLException;
  84
  85   /**
  86    * This method tests whether or not a column is case sensitive in its values.
  87    *
  88    * @param columnIndex The index of the column to test.
  89    * @return <code>true</code> if the column value is case sensitive,
  90    *         <code>false</code> otherwise.
  91    * @exception SQLException If an error occurs.
  92    */
  93   boolean isCaseSensitive(int columnIndex) throws SQLException;
  94
  95   /**
  96    * This method tests whether not the specified column can be used in
  97    * a WHERE clause.
  98    *
  99    * @param columnIndex The index of the column to test.
 100    * @return <code>true</code> if the column may be used in a WHERE clause,
 101    *         <code>false</code> otherwise.
 102    * @exception SQLException If an error occurs.
 103    */
 104   boolean isSearchable(int columnIndex) throws SQLException;
 105
 106   /**
 107    * This method tests whether or not the column stores a monetary value.
 108    *
 109    * @param columnIndex The index of the column to test.
 110    * @return <code>true</code> if the column contains a monetary value,
 111    *         <code>false</code> otherwise.
 112    * @exception SQLException If an error occurs.
 113    */
 114   boolean isCurrency(int columnIndex) throws SQLException;
 115
 116   /**
 117    * This method returns a value indicating whether or not the specified
 118    * column may contain a NULL value.
 119    *
 120    * @param columnIndex The index of the column to test.
 121    * @return A constant indicating whether or not the column can contain NULL,
 122    *         which will be one of <code>columnNoNulls</code>,
 123    *         <code>columnNullable</code>, or <code>columnNullableUnknown</code>.
 124    * @exception SQLException If an error occurs.
 125    */
 126   int isNullable(int columnIndex) throws SQLException;
 127
 128   /**
 129    * This method tests whether or not the value of the specified column
 130    * is signed or unsigned.
 131    *
 132    * @param columnIndex The index of the column to test.
 133    * @return <code>true</code> if the column value is signed, <code>false</code>
 134    *         otherwise.
 135    * @exception SQLException If an error occurs.
 136    */
 137   boolean isSigned(int columnIndex) throws SQLException;
 138
 139   /**
 140    * This method returns the maximum number of characters that can be used
 141    * to display a value in this column.
 142    *
 143    * @param columnIndex The index of the column to check.
 144    * @return The maximum number of characters that can be used to display a
 145    *         value for this column.
 146    * @exception SQLException If an error occurs.
 147    */
 148   int getColumnDisplaySize(int columnIndex) throws SQLException;
 149
 150   /**
 151    * This method returns a string that should be used as a caption for this
 152    * column for user display purposes.
 153    *
 154    * @param columnIndex The index of the column to check.
 155    * @return A display string for the column.
 156    * @exception SQLException If an error occurs.
 157    */
 158   String getColumnLabel(int columnIndex) throws SQLException;
 159
 160   /**
 161    * This method returns the name of the specified column.
 162    *
 163    * @param columnIndex The index of the column to return the name of.
 164    * @return The name of the column.
 165    * @exception SQLException If an error occurs.
 166    */
 167   String getColumnName(int columnIndex) throws SQLException;
 168
 169   /**
 170    * This method returns the name of the schema that contains the specified
 171    * column.
 172    *
 173    * @param columnIndex The index of the column to check the schema name for.
 174    * @return The name of the schema that contains the column.
 175    * @exception SQLException If an error occurs.
 176    */
 177   String getSchemaName(int columnIndex) throws SQLException;
 178
 179   /**
 180    * This method returns the precision of the specified column, which is the
 181    * number of decimal digits it contains.
 182    *
 183    * @param columnIndex The index of the column to check the precision on.
 184    * @return The precision of the specified column.
 185    * @exception SQLException If an error occurs.
 186    */
 187   int getPrecision(int columnIndex) throws SQLException;
 188
 189   /**
 190    * This method returns the scale of the specified column, which is the
 191    * number of digits to the right of the decimal point.
 192    *
 193    * @param columnIndex The index column to check the scale of.
 194    * @return The scale of the column.
 195    * @exception SQLException If an error occurs.
 196    */
 197   int getScale(int columnIndex) throws SQLException;
 198
 199   /**
 200    * This method returns the name of the table containing the specified
 201    * column.
 202    *
 203    * @param columnIndex The index of the column to check the table name for.
 204    * @return The name of the table containing the column.
 205    * @exception SQLException If an error occurs.
 206    */
 207   String getTableName(int columnIndex) throws SQLException;
 208
 209   /**
 210    * This method returns the name of the catalog containing the specified
 211    * column.
 212    *
 213    * @param columnIndex The index of the column to check the catalog name for.
 214    * @return The name of the catalog containing the column.
 215    * @exception SQLException If an error occurs.
 216    */
 217   String getCatalogName(int columnIndex) throws SQLException;
 218
 219   /**
 220    * This method returns the SQL type of the specified column.  This will
 221    * be one of the constants from <code>Types</code>.
 222    *
 223    * @param columnIndex The index of the column to check the SQL type of.
 224    * @return The SQL type for this column.
 225    * @exception SQLException If an error occurs.
 226    * @see Types
 227    */
 228   int getColumnType(int columnIndex) throws SQLException;
 229
 230   /**
 231    * This method returns the name of the SQL type for this column.
 232    *
 233    * @param columnIndex The index of the column to check the SQL type name for.
 234    * @return The name of the SQL type for this column.
 235    * @exception SQLException If an error occurs.
 236    */
 237   String getColumnTypeName(int columnIndex) throws SQLException;
 238
 239   /**
 240    * This method tests whether or not the specified column is read only.
 241    *
 242    * @param columnIndex The index of the column to check.
 243    * @return <code>true</code> if the column is read only, <code>false</code>
 244    *         otherwise.
 245    * @exception SQLException If an error occurs.
 246    */
 247   boolean isReadOnly(int columnIndex) throws SQLException;
 248
 249   /**
 250    * This method tests whether or not the column may be writable.  This
 251    * does not guarantee that a write will be successful.
 252    *
 253    * @param columnIndex The index of the column to check for writability.
 254    * @return <code>true</code> if the column may be writable,
 255    *         <code>false</code> otherwise.
 256    * @exception SQLException If an error occurs.
 257    */
 258   boolean isWritable(int columnIndex) throws SQLException;
 259
 260   /**
 261    * This method tests whether or not the column is writable.  This
 262    * does guarantee that a write will be successful.
 263    *
 264    * @param columnIndex The index of the column to check for writability.
 265    * @return <code>true</code> if the column is writable,
 266    *         <code>false</code> otherwise.
 267    * @exception SQLException If an error occurs.
 268    */
 269   boolean isDefinitelyWritable(int columnIndex) throws SQLException;
 270
 271   /**
 272    * This method returns the name of the Java class which will be used to
 273    * create objects representing the data in this column.
 274    *
 275    * @param columnIndex The index of the column to check.
 276    * @return The name of the Java class that will be used for values in
 277    *         this column.
 278    * @exception SQLException If an error occurs.
 279    */
 280   String getColumnClassName(int columnIndex) throws SQLException;
 281 }