1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package java.sql; 19 20 /** 21 * Provides information about the columns returned in a {@code ResultSet}. 22 */ 23 public interface ResultSetMetaData extends Wrapper { 24 25 /** 26 * Indicates that a column cannot contain {@code NULL} values. 27 */ 28 public static final int columnNoNulls = 0; 29 30 /** 31 * Indicates that a column can contain {@code NULL} values. 32 */ 33 public static final int columnNullable = 1; 34 35 /** 36 * Indicates that it is unknown whether a column can contain {@code NULL}s or not. 37 */ 38 public static final int columnNullableUnknown = 2; 39 40 /** 41 * Returns the title of an indexed column's catalog. 42 * 43 * @param column 44 * the column index, starting at 1. 45 * @return the catalog title. 46 * @throws SQLException 47 * if there is a database error. 48 */ getCatalogName(int column)49 public String getCatalogName(int column) throws SQLException; 50 51 /** 52 * Returns the fully-qualified type of the class that is produced when 53 * invoking {@code ResultSet.getObject} to recover this column's value. 54 * 55 * @param column 56 * the column index, starting at 1. 57 * @return the fully-qualified class name. 58 * @throws SQLException 59 * if there is a database error. 60 * @see ResultSet#getObject 61 */ getColumnClassName(int column)62 public String getColumnClassName(int column) throws SQLException; 63 64 /** 65 * Returns number of columns contained in the associated result set. 66 * 67 * @return the column count. 68 * @throws SQLException 69 * if there is a database error. 70 */ getColumnCount()71 public int getColumnCount() throws SQLException; 72 73 /** 74 * Returns the indexed column's standard maximum width, expressed in number 75 * of characters. 76 * 77 * @param column 78 * the column index, starting at 1. 79 * @return the column's max width. 80 * @throws SQLException 81 * if there is a database error. 82 */ getColumnDisplaySize(int column)83 public int getColumnDisplaySize(int column) throws SQLException; 84 85 /** 86 * Returns a recommended title for the indexed column, to be used when the 87 * title needs to be displayed. 88 * 89 * @param column 90 * the column index, starting at 1. 91 * @return the column's title. 92 * @throws SQLException 93 * if there is a database error. 94 */ getColumnLabel(int column)95 public String getColumnLabel(int column) throws SQLException; 96 97 /** 98 * Returns the title of the indexed column. 99 * 100 * @param column 101 * the column index, starting at 1. 102 * @return the column title. 103 * @throws SQLException 104 * if there is a database error. 105 */ getColumnName(int column)106 public String getColumnName(int column) throws SQLException; 107 108 /** 109 * Returns the type of the indexed column as SQL type code. 110 * 111 * @param column 112 * the column index, starting at 1. 113 * @return the column type code. 114 * @throws SQLException 115 * if there is a database error. 116 * @see Types 117 */ getColumnType(int column)118 public int getColumnType(int column) throws SQLException; 119 120 /** 121 * Returns the type name of the indexed column. 122 * 123 * @param column 124 * the column index, starting at 1. 125 * @return the type name. 126 * @throws SQLException 127 * if there is a database error. 128 */ getColumnTypeName(int column)129 public String getColumnTypeName(int column) throws SQLException; 130 131 /** 132 * Returns the decimal precision of the indexed column. 133 * 134 * @param column 135 * the column index, starting at 1. 136 * @return the precision. 137 * @throws SQLException 138 * if there is a database error. 139 */ getPrecision(int column)140 public int getPrecision(int column) throws SQLException; 141 142 /** 143 * Returns the number of digits to the right of the decimal point of the 144 * indexed column. 145 * 146 * @param column 147 * the column index, starting at 1. 148 * @return number of decimal places. 149 * @throws SQLException 150 * if there is a database error. 151 */ getScale(int column)152 public int getScale(int column) throws SQLException; 153 154 /** 155 * Returns the name of the indexed columns schema. 156 * 157 * @param column 158 * the column index, starting at 1. 159 * @return the name of the columns schema. 160 * @throws SQLException 161 * if there is a database error. 162 */ getSchemaName(int column)163 public String getSchemaName(int column) throws SQLException; 164 165 /** 166 * Returns the title of the indexed columns table. 167 * 168 * @param column 169 * the column index, starting at 1. 170 * @return the table title. 171 * @throws SQLException 172 * if there is a database error. 173 */ getTableName(int column)174 public String getTableName(int column) throws SQLException; 175 176 /** 177 * Returns an indication of whether the indexed column is automatically 178 * incremented and is therefore read-only. 179 * 180 * @param column 181 * the column index, starting at 1. 182 * @return {@code true} if it is automatically numbered, {@code false} 183 * otherwise. 184 * @throws SQLException 185 * if there is a database error. 186 */ isAutoIncrement(int column)187 public boolean isAutoIncrement(int column) throws SQLException; 188 189 /** 190 * Returns an indication of whether the case of the indexed column is 191 * important. 192 * 193 * @param column 194 * the column index, starting at 1. 195 * @return {@code true} if case matters, {@code false} otherwise. 196 * @throws SQLException 197 * if there is a database error. 198 */ isCaseSensitive(int column)199 public boolean isCaseSensitive(int column) throws SQLException; 200 201 /** 202 * Returns whether the indexed column contains a monetary amount. 203 * 204 * @param column 205 * the column index, starting at 1. 206 * @return {@code true} if it is a monetary value, {@code false} otherwise. 207 * @throws SQLException 208 * if there is a database error. 209 */ isCurrency(int column)210 public boolean isCurrency(int column) throws SQLException; 211 212 /** 213 * Returns an indication of whether writing to the indexed column is 214 * guaranteed to be successful. 215 * 216 * @param column 217 * the column index, starting at 1. 218 * @return {@code true} if the write is guaranteed, {@code false} otherwise. 219 * @throws SQLException 220 * if there is a database error. 221 */ isDefinitelyWritable(int column)222 public boolean isDefinitelyWritable(int column) throws SQLException; 223 224 /** 225 * Returns whether the indexed column is nullable. 226 * 227 * @param column 228 * the column index, starting at 1. 229 * @return {@code true} if it is nullable, {@code false} otherwise. 230 * @throws SQLException 231 * if there is a database error. 232 */ isNullable(int column)233 public int isNullable(int column) throws SQLException; 234 235 /** 236 * Returns an indication of whether writing to the indexed column is 237 * guaranteed to be unsuccessful. 238 * 239 * @param column 240 * the column index, starting at 1. 241 * @return {@code true} if the column is read-only, {@code false} otherwise. 242 * @throws SQLException 243 * if there is a database error. 244 */ isReadOnly(int column)245 public boolean isReadOnly(int column) throws SQLException; 246 247 /** 248 * Returns an indication of whether the indexed column is searchable. 249 * 250 * @param column 251 * the column index, starting at 1. 252 * @return {@code true} if the indexed column is searchable, {@code false} 253 * otherwise. 254 * @throws SQLException 255 * if there is a database error. 256 */ isSearchable(int column)257 public boolean isSearchable(int column) throws SQLException; 258 259 /** 260 * Returns an indication of whether the values contained in the indexed 261 * column are signed. 262 * 263 * @param column 264 * the column index, starting at 1. 265 * @return {@code true} if they are signed, {@code false} otherwise. 266 * @throws SQLException 267 * if there is a database error. 268 */ isSigned(int column)269 public boolean isSigned(int column) throws SQLException; 270 271 /** 272 * Returns an indication of whether writing to the indexed column is 273 * possible. 274 * 275 * @param column 276 * the column index, starting at 1. 277 * @return {@code true} if it is possible to write, {@code false} otherwise. 278 * @throws SQLException 279 * if there is a database error. 280 */ isWritable(int column)281 public boolean isWritable(int column) throws SQLException; 282 } 283