The Android Open Source Project | 9066cfe | 2009-03-03 19:31:44 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package android.database.sqlite; |
| 18 | |
| 19 | import android.database.Cursor; |
| 20 | import android.database.DatabaseUtils; |
| 21 | import android.database.sqlite.SQLiteDatabase; |
| 22 | import android.provider.BaseColumns; |
| 23 | import android.text.TextUtils; |
| 24 | import android.util.Config; |
| 25 | import android.util.Log; |
| 26 | |
| 27 | import java.util.Iterator; |
| 28 | import java.util.Map; |
| 29 | import java.util.Set; |
| 30 | import java.util.Map.Entry; |
| 31 | |
| 32 | /** |
| 33 | * This is a convience class that helps build SQL queries to be sent to |
| 34 | * {@link SQLiteDatabase} objects. |
| 35 | */ |
| 36 | public class SQLiteQueryBuilder |
| 37 | { |
| 38 | private static final String TAG = "SQLiteQueryBuilder"; |
| 39 | |
| 40 | private Map<String, String> mProjectionMap = null; |
| 41 | private String mTables = ""; |
| 42 | private StringBuilder mWhereClause = new StringBuilder(64); |
| 43 | private boolean mDistinct; |
| 44 | private SQLiteDatabase.CursorFactory mFactory; |
| 45 | |
| 46 | public SQLiteQueryBuilder() { |
| 47 | mDistinct = false; |
| 48 | mFactory = null; |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Mark the query as DISTINCT. |
| 53 | * |
| 54 | * @param distinct if true the query is DISTINCT, otherwise it isn't |
| 55 | */ |
| 56 | public void setDistinct(boolean distinct) { |
| 57 | mDistinct = distinct; |
| 58 | } |
| 59 | |
| 60 | /** |
| 61 | * Returns the list of tables being queried |
| 62 | * |
| 63 | * @return the list of tables being queried |
| 64 | */ |
| 65 | public String getTables() { |
| 66 | return mTables; |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * Sets the list of tables to query. Multiple tables can be specified to perform a join. |
| 71 | * For example: |
| 72 | * setTables("foo, bar") |
| 73 | * setTables("foo LEFT OUTER JOIN bar ON (foo.id = bar.foo_id)") |
| 74 | * |
| 75 | * @param inTables the list of tables to query on |
| 76 | */ |
| 77 | public void setTables(String inTables) { |
| 78 | mTables = inTables; |
| 79 | } |
| 80 | |
| 81 | /** |
| 82 | * Append a chunk to the WHERE clause of the query. All chunks appended are surrounded |
| 83 | * by parenthesis and ANDed with the selection passed to {@link #query}. The final |
| 84 | * WHERE clause looks like: |
| 85 | * |
| 86 | * WHERE (<append chunk 1><append chunk2>) AND (<query() selection parameter>) |
| 87 | * |
| 88 | * @param inWhere the chunk of text to append to the WHERE clause. |
| 89 | */ |
| 90 | public void appendWhere(CharSequence inWhere) { |
| 91 | if (mWhereClause.length() == 0) { |
| 92 | mWhereClause.append('('); |
| 93 | } |
| 94 | mWhereClause.append(inWhere); |
| 95 | } |
| 96 | |
| 97 | /** |
| 98 | * Append a chunk to the WHERE clause of the query. All chunks appended are surrounded |
| 99 | * by parenthesis and ANDed with the selection passed to {@link #query}. The final |
| 100 | * WHERE clause looks like: |
| 101 | * |
| 102 | * WHERE (<append chunk 1><append chunk2>) AND (<query() selection parameter>) |
| 103 | * |
| 104 | * @param inWhere the chunk of text to append to the WHERE clause. it will be escaped |
| 105 | * to avoid SQL injection attacks |
| 106 | */ |
| 107 | public void appendWhereEscapeString(String inWhere) { |
| 108 | if (mWhereClause.length() == 0) { |
| 109 | mWhereClause.append('('); |
| 110 | } |
| 111 | DatabaseUtils.appendEscapedSQLString(mWhereClause, inWhere); |
| 112 | } |
| 113 | |
| 114 | /** |
| 115 | * Sets the projection map for the query. The projection map maps |
| 116 | * from column names that the caller passes into query to database |
| 117 | * column names. This is useful for renaming columns as well as |
| 118 | * disambiguating column names when doing joins. For example you |
| 119 | * could map "name" to "people.name". If a projection map is set |
| 120 | * it must contain all column names the user may request, even if |
| 121 | * the key and value are the same. |
| 122 | * |
| 123 | * @param columnMap maps from the user column names to the database column names |
| 124 | */ |
| 125 | public void setProjectionMap(Map<String, String> columnMap) { |
| 126 | mProjectionMap = columnMap; |
| 127 | } |
| 128 | |
| 129 | /** |
| 130 | * Sets the cursor factory to be used for the query. You can use |
| 131 | * one factory for all queries on a database but it is normally |
| 132 | * easier to specify the factory when doing this query. @param |
| 133 | * factory the factor to use |
| 134 | */ |
| 135 | public void setCursorFactory(SQLiteDatabase.CursorFactory factory) { |
| 136 | mFactory = factory; |
| 137 | } |
| 138 | |
| 139 | /** |
| 140 | * Build an SQL query string from the given clauses. |
| 141 | * |
| 142 | * @param distinct true if you want each row to be unique, false otherwise. |
| 143 | * @param tables The table names to compile the query against. |
| 144 | * @param columns A list of which columns to return. Passing null will |
| 145 | * return all columns, which is discouraged to prevent reading |
| 146 | * data from storage that isn't going to be used. |
| 147 | * @param where A filter declaring which rows to return, formatted as an SQL |
| 148 | * WHERE clause (excluding the WHERE itself). Passing null will |
| 149 | * return all rows for the given URL. |
| 150 | * @param groupBy A filter declaring how to group rows, formatted as an SQL |
| 151 | * GROUP BY clause (excluding the GROUP BY itself). Passing null |
| 152 | * will cause the rows to not be grouped. |
| 153 | * @param having A filter declare which row groups to include in the cursor, |
| 154 | * if row grouping is being used, formatted as an SQL HAVING |
| 155 | * clause (excluding the HAVING itself). Passing null will cause |
| 156 | * all row groups to be included, and is required when row |
| 157 | * grouping is not being used. |
| 158 | * @param orderBy How to order the rows, formatted as an SQL ORDER BY clause |
| 159 | * (excluding the ORDER BY itself). Passing null will use the |
| 160 | * default sort order, which may be unordered. |
| 161 | * @param limit Limits the number of rows returned by the query, |
| 162 | * formatted as LIMIT clause. Passing null denotes no LIMIT clause. |
| 163 | * @return the SQL query string |
| 164 | */ |
| 165 | public static String buildQueryString( |
| 166 | boolean distinct, String tables, String[] columns, String where, |
| 167 | String groupBy, String having, String orderBy, String limit) { |
| 168 | if (TextUtils.isEmpty(groupBy) && !TextUtils.isEmpty(having)) { |
| 169 | throw new IllegalArgumentException( |
| 170 | "HAVING clauses are only permitted when using a groupBy clause"); |
| 171 | } |
| 172 | |
| 173 | StringBuilder query = new StringBuilder(120); |
| 174 | |
| 175 | query.append("SELECT "); |
| 176 | if (distinct) { |
| 177 | query.append("DISTINCT "); |
| 178 | } |
| 179 | if (columns != null && columns.length != 0) { |
| 180 | appendColumns(query, columns); |
| 181 | } else { |
| 182 | query.append("* "); |
| 183 | } |
| 184 | query.append("FROM "); |
| 185 | query.append(tables); |
| 186 | appendClause(query, " WHERE ", where); |
| 187 | appendClause(query, " GROUP BY ", groupBy); |
| 188 | appendClause(query, " HAVING ", having); |
| 189 | appendClause(query, " ORDER BY ", orderBy); |
| 190 | appendClauseEscapeClause(query, " LIMIT ", limit); |
| 191 | |
| 192 | return query.toString(); |
| 193 | } |
| 194 | |
| 195 | private static void appendClause(StringBuilder s, String name, String clause) { |
| 196 | if (!TextUtils.isEmpty(clause)) { |
| 197 | s.append(name); |
| 198 | s.append(clause); |
| 199 | } |
| 200 | } |
| 201 | |
| 202 | private static void appendClauseEscapeClause(StringBuilder s, String name, String clause) { |
| 203 | if (!TextUtils.isEmpty(clause)) { |
| 204 | s.append(name); |
| 205 | DatabaseUtils.appendEscapedSQLString(s, clause); |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | /** |
| 210 | * Add the names that are non-null in columns to s, separating |
| 211 | * them with commas. |
| 212 | */ |
| 213 | public static void appendColumns(StringBuilder s, String[] columns) { |
| 214 | int n = columns.length; |
| 215 | |
| 216 | for (int i = 0; i < n; i++) { |
| 217 | String column = columns[i]; |
| 218 | |
| 219 | if (column != null) { |
| 220 | if (i > 0) { |
| 221 | s.append(", "); |
| 222 | } |
| 223 | s.append(column); |
| 224 | } |
| 225 | } |
| 226 | s.append(' '); |
| 227 | } |
| 228 | |
| 229 | /** |
| 230 | * Perform a query by combining all current settings and the |
| 231 | * information passed into this method. |
| 232 | * |
| 233 | * @param db the database to query on |
| 234 | * @param projectionIn A list of which columns to return. Passing |
| 235 | * null will return all columns, which is discouraged to prevent |
| 236 | * reading data from storage that isn't going to be used. |
| 237 | * @param selection A filter declaring which rows to return, |
| 238 | * formatted as an SQL WHERE clause (excluding the WHERE |
| 239 | * itself). Passing null will return all rows for the given URL. |
| 240 | * @param selectionArgs You may include ?s in selection, which |
| 241 | * will be replaced by the values from selectionArgs, in order |
| 242 | * that they appear in the selection. The values will be bound |
| 243 | * as Strings. |
| 244 | * @param groupBy A filter declaring how to group rows, formatted |
| 245 | * as an SQL GROUP BY clause (excluding the GROUP BY |
| 246 | * itself). Passing null will cause the rows to not be grouped. |
| 247 | * @param having A filter declare which row groups to include in |
| 248 | * the cursor, if row grouping is being used, formatted as an |
| 249 | * SQL HAVING clause (excluding the HAVING itself). Passing |
| 250 | * null will cause all row groups to be included, and is |
| 251 | * required when row grouping is not being used. |
| 252 | * @param sortOrder How to order the rows, formatted as an SQL |
| 253 | * ORDER BY clause (excluding the ORDER BY itself). Passing null |
| 254 | * will use the default sort order, which may be unordered. |
| 255 | * @return a cursor over the result set |
| 256 | * @see android.content.ContentResolver#query(android.net.Uri, String[], |
| 257 | * String, String[], String) |
| 258 | */ |
| 259 | public Cursor query(SQLiteDatabase db, String[] projectionIn, |
| 260 | String selection, String[] selectionArgs, String groupBy, |
| 261 | String having, String sortOrder) { |
| 262 | return query(db, projectionIn, selection, selectionArgs, groupBy, having, sortOrder, |
| 263 | null /* limit */); |
| 264 | } |
| 265 | |
| 266 | /** |
| 267 | * Perform a query by combining all current settings and the |
| 268 | * information passed into this method. |
| 269 | * |
| 270 | * @param db the database to query on |
| 271 | * @param projectionIn A list of which columns to return. Passing |
| 272 | * null will return all columns, which is discouraged to prevent |
| 273 | * reading data from storage that isn't going to be used. |
| 274 | * @param selection A filter declaring which rows to return, |
| 275 | * formatted as an SQL WHERE clause (excluding the WHERE |
| 276 | * itself). Passing null will return all rows for the given URL. |
| 277 | * @param selectionArgs You may include ?s in selection, which |
| 278 | * will be replaced by the values from selectionArgs, in order |
| 279 | * that they appear in the selection. The values will be bound |
| 280 | * as Strings. |
| 281 | * @param groupBy A filter declaring how to group rows, formatted |
| 282 | * as an SQL GROUP BY clause (excluding the GROUP BY |
| 283 | * itself). Passing null will cause the rows to not be grouped. |
| 284 | * @param having A filter declare which row groups to include in |
| 285 | * the cursor, if row grouping is being used, formatted as an |
| 286 | * SQL HAVING clause (excluding the HAVING itself). Passing |
| 287 | * null will cause all row groups to be included, and is |
| 288 | * required when row grouping is not being used. |
| 289 | * @param sortOrder How to order the rows, formatted as an SQL |
| 290 | * ORDER BY clause (excluding the ORDER BY itself). Passing null |
| 291 | * will use the default sort order, which may be unordered. |
| 292 | * @param limit Limits the number of rows returned by the query, |
| 293 | * formatted as LIMIT clause. Passing null denotes no LIMIT clause. |
| 294 | * @return a cursor over the result set |
| 295 | * @see android.content.ContentResolver#query(android.net.Uri, String[], |
| 296 | * String, String[], String) |
| 297 | */ |
| 298 | public Cursor query(SQLiteDatabase db, String[] projectionIn, |
| 299 | String selection, String[] selectionArgs, String groupBy, |
| 300 | String having, String sortOrder, String limit) { |
| 301 | if (mTables == null) { |
| 302 | return null; |
| 303 | } |
| 304 | |
| 305 | String sql = buildQuery( |
| 306 | projectionIn, selection, selectionArgs, groupBy, having, |
| 307 | sortOrder, limit); |
| 308 | |
| 309 | if (Log.isLoggable(TAG, Log.DEBUG)) { |
| 310 | Log.d(TAG, "Performing query: " + sql); |
| 311 | } |
| 312 | return db.rawQueryWithFactory( |
| 313 | mFactory, sql, selectionArgs, |
| 314 | SQLiteDatabase.findEditTable(mTables)); |
| 315 | } |
| 316 | |
| 317 | /** |
| 318 | * Construct a SELECT statement suitable for use in a group of |
| 319 | * SELECT statements that will be joined through UNION operators |
| 320 | * in buildUnionQuery. |
| 321 | * |
| 322 | * @param projectionIn A list of which columns to return. Passing |
| 323 | * null will return all columns, which is discouraged to |
| 324 | * prevent reading data from storage that isn't going to be |
| 325 | * used. |
| 326 | * @param selection A filter declaring which rows to return, |
| 327 | * formatted as an SQL WHERE clause (excluding the WHERE |
| 328 | * itself). Passing null will return all rows for the given |
| 329 | * URL. |
| 330 | * @param selectionArgs You may include ?s in selection, which |
| 331 | * will be replaced by the values from selectionArgs, in order |
| 332 | * that they appear in the selection. The values will be bound |
| 333 | * as Strings. |
| 334 | * @param groupBy A filter declaring how to group rows, formatted |
| 335 | * as an SQL GROUP BY clause (excluding the GROUP BY itself). |
| 336 | * Passing null will cause the rows to not be grouped. |
| 337 | * @param having A filter declare which row groups to include in |
| 338 | * the cursor, if row grouping is being used, formatted as an |
| 339 | * SQL HAVING clause (excluding the HAVING itself). Passing |
| 340 | * null will cause all row groups to be included, and is |
| 341 | * required when row grouping is not being used. |
| 342 | * @param sortOrder How to order the rows, formatted as an SQL |
| 343 | * ORDER BY clause (excluding the ORDER BY itself). Passing null |
| 344 | * will use the default sort order, which may be unordered. |
| 345 | * @param limit Limits the number of rows returned by the query, |
| 346 | * formatted as LIMIT clause. Passing null denotes no LIMIT clause. |
| 347 | * @return the resulting SQL SELECT statement |
| 348 | */ |
| 349 | public String buildQuery( |
| 350 | String[] projectionIn, String selection, String[] selectionArgs, |
| 351 | String groupBy, String having, String sortOrder, String limit) { |
| 352 | String[] projection = computeProjection(projectionIn); |
| 353 | |
| 354 | if (mWhereClause.length() > 0) { |
| 355 | mWhereClause.append(')'); |
| 356 | } |
| 357 | |
| 358 | // Tack on the user's selection, if present. |
| 359 | if (selection != null && selection.length() > 0) { |
| 360 | if (mWhereClause.length() > 0) { |
| 361 | mWhereClause.append(" AND "); |
| 362 | } |
| 363 | |
| 364 | mWhereClause.append('('); |
| 365 | mWhereClause.append(selection); |
| 366 | mWhereClause.append(')'); |
| 367 | } |
| 368 | |
| 369 | return buildQueryString( |
| 370 | mDistinct, mTables, projection, mWhereClause.toString(), |
| 371 | groupBy, having, sortOrder, limit); |
| 372 | } |
| 373 | |
| 374 | /** |
| 375 | * Construct a SELECT statement suitable for use in a group of |
| 376 | * SELECT statements that will be joined through UNION operators |
| 377 | * in buildUnionQuery. |
| 378 | * |
| 379 | * @param typeDiscriminatorColumn the name of the result column |
| 380 | * whose cells will contain the name of the table from which |
| 381 | * each row was drawn. |
| 382 | * @param unionColumns the names of the columns to appear in the |
| 383 | * result. This may include columns that do not appear in the |
| 384 | * table this SELECT is querying (i.e. mTables), but that do |
| 385 | * appear in one of the other tables in the UNION query that we |
| 386 | * are constructing. |
| 387 | * @param columnsPresentInTable a Set of the names of the columns |
| 388 | * that appear in this table (i.e. in the table whose name is |
| 389 | * mTables). Since columns in unionColumns include columns that |
| 390 | * appear only in other tables, we use this array to distinguish |
| 391 | * which ones actually are present. Other columns will have |
| 392 | * NULL values for results from this subquery. |
| 393 | * @param computedColumnsOffset all columns in unionColumns before |
| 394 | * this index are included under the assumption that they're |
| 395 | * computed and therefore won't appear in columnsPresentInTable, |
| 396 | * e.g. "date * 1000 as normalized_date" |
| 397 | * @param typeDiscriminatorValue the value used for the |
| 398 | * type-discriminator column in this subquery |
| 399 | * @param selection A filter declaring which rows to return, |
| 400 | * formatted as an SQL WHERE clause (excluding the WHERE |
| 401 | * itself). Passing null will return all rows for the given |
| 402 | * URL. |
| 403 | * @param selectionArgs You may include ?s in selection, which |
| 404 | * will be replaced by the values from selectionArgs, in order |
| 405 | * that they appear in the selection. The values will be bound |
| 406 | * as Strings. |
| 407 | * @param groupBy A filter declaring how to group rows, formatted |
| 408 | * as an SQL GROUP BY clause (excluding the GROUP BY itself). |
| 409 | * Passing null will cause the rows to not be grouped. |
| 410 | * @param having A filter declare which row groups to include in |
| 411 | * the cursor, if row grouping is being used, formatted as an |
| 412 | * SQL HAVING clause (excluding the HAVING itself). Passing |
| 413 | * null will cause all row groups to be included, and is |
| 414 | * required when row grouping is not being used. |
| 415 | * @return the resulting SQL SELECT statement |
| 416 | */ |
| 417 | public String buildUnionSubQuery( |
| 418 | String typeDiscriminatorColumn, |
| 419 | String[] unionColumns, |
| 420 | Set<String> columnsPresentInTable, |
| 421 | int computedColumnsOffset, |
| 422 | String typeDiscriminatorValue, |
| 423 | String selection, |
| 424 | String[] selectionArgs, |
| 425 | String groupBy, |
| 426 | String having) { |
| 427 | int unionColumnsCount = unionColumns.length; |
| 428 | String[] projectionIn = new String[unionColumnsCount]; |
| 429 | |
| 430 | for (int i = 0; i < unionColumnsCount; i++) { |
| 431 | String unionColumn = unionColumns[i]; |
| 432 | |
| 433 | if (unionColumn.equals(typeDiscriminatorColumn)) { |
| 434 | projectionIn[i] = "'" + typeDiscriminatorValue + "' AS " |
| 435 | + typeDiscriminatorColumn; |
| 436 | } else if (i <= computedColumnsOffset |
| 437 | || columnsPresentInTable.contains(unionColumn)) { |
| 438 | projectionIn[i] = unionColumn; |
| 439 | } else { |
| 440 | projectionIn[i] = "NULL AS " + unionColumn; |
| 441 | } |
| 442 | } |
| 443 | return buildQuery( |
| 444 | projectionIn, selection, selectionArgs, groupBy, having, |
| 445 | null /* sortOrder */, |
| 446 | null /* limit */); |
| 447 | } |
| 448 | |
| 449 | /** |
| 450 | * Given a set of subqueries, all of which are SELECT statements, |
| 451 | * construct a query that returns the union of what those |
| 452 | * subqueries return. |
| 453 | * @param subQueries an array of SQL SELECT statements, all of |
| 454 | * which must have the same columns as the same positions in |
| 455 | * their results |
| 456 | * @param sortOrder How to order the rows, formatted as an SQL |
| 457 | * ORDER BY clause (excluding the ORDER BY itself). Passing |
| 458 | * null will use the default sort order, which may be unordered. |
| 459 | * @param limit The limit clause, which applies to the entire union result set |
| 460 | * |
| 461 | * @return the resulting SQL SELECT statement |
| 462 | */ |
| 463 | public String buildUnionQuery(String[] subQueries, String sortOrder, String limit) { |
| 464 | StringBuilder query = new StringBuilder(128); |
| 465 | int subQueryCount = subQueries.length; |
| 466 | String unionOperator = mDistinct ? " UNION " : " UNION ALL "; |
| 467 | |
| 468 | for (int i = 0; i < subQueryCount; i++) { |
| 469 | if (i > 0) { |
| 470 | query.append(unionOperator); |
| 471 | } |
| 472 | query.append(subQueries[i]); |
| 473 | } |
| 474 | appendClause(query, " ORDER BY ", sortOrder); |
| 475 | appendClause(query, " LIMIT ", limit); |
| 476 | return query.toString(); |
| 477 | } |
| 478 | |
| 479 | private String[] computeProjection(String[] projectionIn) { |
| 480 | if (projectionIn != null && projectionIn.length > 0) { |
| 481 | if (mProjectionMap != null) { |
| 482 | String[] projection = new String[projectionIn.length]; |
| 483 | int length = projectionIn.length; |
| 484 | |
| 485 | for (int i = 0; i < length; i++) { |
| 486 | String userColumn = projectionIn[i]; |
| 487 | String column = mProjectionMap.get(userColumn); |
| 488 | |
| 489 | if (column == null) { |
| 490 | throw new IllegalArgumentException( |
| 491 | "Invalid column " + projectionIn[i]); |
| 492 | } else { |
| 493 | projection[i] = column; |
| 494 | } |
| 495 | } |
| 496 | return projection; |
| 497 | } else { |
| 498 | return projectionIn; |
| 499 | } |
| 500 | } else if (mProjectionMap != null) { |
| 501 | // Return all columns in projection map. |
| 502 | Set<Entry<String, String>> entrySet = mProjectionMap.entrySet(); |
| 503 | String[] projection = new String[entrySet.size()]; |
| 504 | Iterator<Entry<String, String>> entryIter = entrySet.iterator(); |
| 505 | int i = 0; |
| 506 | |
| 507 | while (entryIter.hasNext()) { |
| 508 | Entry<String, String> entry = entryIter.next(); |
| 509 | |
| 510 | // Don't include the _count column when people ask for no projection. |
| 511 | if (entry.getKey().equals(BaseColumns._COUNT)) { |
| 512 | continue; |
| 513 | } |
| 514 | projection[i++] = entry.getValue(); |
| 515 | } |
| 516 | return projection; |
| 517 | } |
| 518 | return null; |
| 519 | } |
| 520 | } |