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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: }