1 | /* |
2 | * Copyright 2004-2014 H2 Group. Multiple-Licensed under the MPL 2.0, |
3 | * and the EPL 1.0 (http://h2database.com/html/license.html). |
4 | * Initial Developer: H2 Group |
5 | */ |
6 | package org.h2.expression; |
7 | |
8 | import java.util.HashMap; |
9 | |
10 | import org.h2.api.ErrorCode; |
11 | import org.h2.command.Parser; |
12 | import org.h2.command.dml.Select; |
13 | import org.h2.command.dml.SelectListColumnResolver; |
14 | import org.h2.engine.Database; |
15 | import org.h2.engine.Session; |
16 | import org.h2.index.IndexCondition; |
17 | import org.h2.message.DbException; |
18 | import org.h2.schema.Constant; |
19 | import org.h2.schema.Schema; |
20 | import org.h2.table.Column; |
21 | import org.h2.table.ColumnResolver; |
22 | import org.h2.table.Table; |
23 | import org.h2.table.TableFilter; |
24 | import org.h2.value.Value; |
25 | import org.h2.value.ValueBoolean; |
26 | |
27 | /** |
28 | * A expression that represents a column of a table or view. |
29 | */ |
30 | public class ExpressionColumn extends Expression { |
31 | |
32 | private final Database database; |
33 | private final String schemaName; |
34 | private final String tableAlias; |
35 | private final String columnName; |
36 | private ColumnResolver columnResolver; |
37 | private int queryLevel; |
38 | private Column column; |
39 | private boolean evaluatable; |
40 | |
41 | public ExpressionColumn(Database database, Column column) { |
42 | this.database = database; |
43 | this.column = column; |
44 | this.schemaName = null; |
45 | this.tableAlias = null; |
46 | this.columnName = null; |
47 | } |
48 | |
49 | public ExpressionColumn(Database database, String schemaName, |
50 | String tableAlias, String columnName) { |
51 | this.database = database; |
52 | this.schemaName = schemaName; |
53 | this.tableAlias = tableAlias; |
54 | this.columnName = columnName; |
55 | } |
56 | |
57 | @Override |
58 | public String getSQL() { |
59 | String sql; |
60 | boolean quote = database.getSettings().databaseToUpper; |
61 | if (column != null) { |
62 | sql = column.getSQL(); |
63 | } else { |
64 | sql = quote ? Parser.quoteIdentifier(columnName) : columnName; |
65 | } |
66 | if (tableAlias != null) { |
67 | String a = quote ? Parser.quoteIdentifier(tableAlias) : tableAlias; |
68 | sql = a + "." + sql; |
69 | } |
70 | if (schemaName != null) { |
71 | String s = quote ? Parser.quoteIdentifier(schemaName) : schemaName; |
72 | sql = s + "." + sql; |
73 | } |
74 | return sql; |
75 | } |
76 | |
77 | public TableFilter getTableFilter() { |
78 | return columnResolver == null ? null : columnResolver.getTableFilter(); |
79 | } |
80 | |
81 | @Override |
82 | public void mapColumns(ColumnResolver resolver, int level) { |
83 | if (tableAlias != null && !database.equalsIdentifiers( |
84 | tableAlias, resolver.getTableAlias())) { |
85 | return; |
86 | } |
87 | if (schemaName != null && !database.equalsIdentifiers( |
88 | schemaName, resolver.getSchemaName())) { |
89 | return; |
90 | } |
91 | for (Column col : resolver.getColumns()) { |
92 | String n = col.getName(); |
93 | if (database.equalsIdentifiers(columnName, n)) { |
94 | mapColumn(resolver, col, level); |
95 | return; |
96 | } |
97 | } |
98 | if (database.equalsIdentifiers(Column.ROWID, columnName)) { |
99 | Column col = resolver.getRowIdColumn(); |
100 | if (col != null) { |
101 | mapColumn(resolver, col, level); |
102 | return; |
103 | } |
104 | } |
105 | Column[] columns = resolver.getSystemColumns(); |
106 | for (int i = 0; columns != null && i < columns.length; i++) { |
107 | Column col = columns[i]; |
108 | if (database.equalsIdentifiers(columnName, col.getName())) { |
109 | mapColumn(resolver, col, level); |
110 | return; |
111 | } |
112 | } |
113 | } |
114 | |
115 | private void mapColumn(ColumnResolver resolver, Column col, int level) { |
116 | if (this.columnResolver == null) { |
117 | queryLevel = level; |
118 | column = col; |
119 | this.columnResolver = resolver; |
120 | } else if (queryLevel == level && this.columnResolver != resolver) { |
121 | if (resolver instanceof SelectListColumnResolver) { |
122 | // ignore - already mapped, that's ok |
123 | } else { |
124 | throw DbException.get(ErrorCode.AMBIGUOUS_COLUMN_NAME_1, columnName); |
125 | } |
126 | } |
127 | } |
128 | |
129 | @Override |
130 | public Expression optimize(Session session) { |
131 | if (columnResolver == null) { |
132 | Schema schema = session.getDatabase().findSchema( |
133 | tableAlias == null ? session.getCurrentSchemaName() : tableAlias); |
134 | if (schema != null) { |
135 | Constant constant = schema.findConstant(columnName); |
136 | if (constant != null) { |
137 | return constant.getValue(); |
138 | } |
139 | } |
140 | String name = columnName; |
141 | if (tableAlias != null) { |
142 | name = tableAlias + "." + name; |
143 | if (schemaName != null) { |
144 | name = schemaName + "." + name; |
145 | } |
146 | } |
147 | throw DbException.get(ErrorCode.COLUMN_NOT_FOUND_1, name); |
148 | } |
149 | return columnResolver.optimize(this, column); |
150 | } |
151 | |
152 | @Override |
153 | public void updateAggregate(Session session) { |
154 | Value now = columnResolver.getValue(column); |
155 | Select select = columnResolver.getSelect(); |
156 | if (select == null) { |
157 | throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL()); |
158 | } |
159 | HashMap<Expression, Object> values = select.getCurrentGroup(); |
160 | if (values == null) { |
161 | // this is a different level (the enclosing query) |
162 | return; |
163 | } |
164 | Value v = (Value) values.get(this); |
165 | if (v == null) { |
166 | values.put(this, now); |
167 | } else { |
168 | if (!database.areEqual(now, v)) { |
169 | throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL()); |
170 | } |
171 | } |
172 | } |
173 | |
174 | @Override |
175 | public Value getValue(Session session) { |
176 | Select select = columnResolver.getSelect(); |
177 | if (select != null) { |
178 | HashMap<Expression, Object> values = select.getCurrentGroup(); |
179 | if (values != null) { |
180 | Value v = (Value) values.get(this); |
181 | if (v != null) { |
182 | return v; |
183 | } |
184 | } |
185 | } |
186 | Value value = columnResolver.getValue(column); |
187 | if (value == null) { |
188 | columnResolver.getValue(column); |
189 | throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL()); |
190 | } |
191 | return value; |
192 | } |
193 | |
194 | @Override |
195 | public int getType() { |
196 | return column.getType(); |
197 | } |
198 | |
199 | @Override |
200 | public void setEvaluatable(TableFilter tableFilter, boolean b) { |
201 | if (columnResolver != null && tableFilter == columnResolver.getTableFilter()) { |
202 | evaluatable = b; |
203 | } |
204 | } |
205 | |
206 | public Column getColumn() { |
207 | return column; |
208 | } |
209 | |
210 | @Override |
211 | public int getScale() { |
212 | return column.getScale(); |
213 | } |
214 | |
215 | @Override |
216 | public long getPrecision() { |
217 | return column.getPrecision(); |
218 | } |
219 | |
220 | @Override |
221 | public int getDisplaySize() { |
222 | return column.getDisplaySize(); |
223 | } |
224 | |
225 | public String getOriginalColumnName() { |
226 | return columnName; |
227 | } |
228 | |
229 | public String getOriginalTableAliasName() { |
230 | return tableAlias; |
231 | } |
232 | |
233 | @Override |
234 | public String getColumnName() { |
235 | return columnName != null ? columnName : column.getName(); |
236 | } |
237 | |
238 | @Override |
239 | public String getSchemaName() { |
240 | Table table = column.getTable(); |
241 | return table == null ? null : table.getSchema().getName(); |
242 | } |
243 | |
244 | @Override |
245 | public String getTableName() { |
246 | Table table = column.getTable(); |
247 | return table == null ? null : table.getName(); |
248 | } |
249 | |
250 | @Override |
251 | public String getAlias() { |
252 | if (column != null) { |
253 | return column.getName(); |
254 | } |
255 | if (tableAlias != null) { |
256 | return tableAlias + "." + columnName; |
257 | } |
258 | return columnName; |
259 | } |
260 | |
261 | @Override |
262 | public boolean isAutoIncrement() { |
263 | return column.getSequence() != null; |
264 | } |
265 | |
266 | @Override |
267 | public int getNullable() { |
268 | return column.isNullable() ? Column.NULLABLE : Column.NOT_NULLABLE; |
269 | } |
270 | |
271 | @Override |
272 | public boolean isEverything(ExpressionVisitor visitor) { |
273 | switch (visitor.getType()) { |
274 | case ExpressionVisitor.OPTIMIZABLE_MIN_MAX_COUNT_ALL: |
275 | return false; |
276 | case ExpressionVisitor.READONLY: |
277 | case ExpressionVisitor.DETERMINISTIC: |
278 | case ExpressionVisitor.QUERY_COMPARABLE: |
279 | return true; |
280 | case ExpressionVisitor.INDEPENDENT: |
281 | return this.queryLevel < visitor.getQueryLevel(); |
282 | case ExpressionVisitor.EVALUATABLE: |
283 | // if the current value is known (evaluatable set) |
284 | // or if this columns belongs to a 'higher level' query and is |
285 | // therefore just a parameter |
286 | if (database.getSettings().nestedJoins) { |
287 | if (visitor.getQueryLevel() < this.queryLevel) { |
288 | return true; |
289 | } |
290 | if (getTableFilter() == null) { |
291 | return false; |
292 | } |
293 | return getTableFilter().isEvaluatable(); |
294 | } |
295 | return evaluatable || visitor.getQueryLevel() < this.queryLevel; |
296 | case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID: |
297 | visitor.addDataModificationId(column.getTable().getMaxDataModificationId()); |
298 | return true; |
299 | case ExpressionVisitor.NOT_FROM_RESOLVER: |
300 | return columnResolver != visitor.getResolver(); |
301 | case ExpressionVisitor.GET_DEPENDENCIES: |
302 | if (column != null) { |
303 | visitor.addDependency(column.getTable()); |
304 | } |
305 | return true; |
306 | case ExpressionVisitor.GET_COLUMNS: |
307 | visitor.addColumn(column); |
308 | return true; |
309 | default: |
310 | throw DbException.throwInternalError("type=" + visitor.getType()); |
311 | } |
312 | } |
313 | |
314 | @Override |
315 | public int getCost() { |
316 | return 2; |
317 | } |
318 | |
319 | @Override |
320 | public void createIndexConditions(Session session, TableFilter filter) { |
321 | TableFilter tf = getTableFilter(); |
322 | if (filter == tf && column.getType() == Value.BOOLEAN) { |
323 | IndexCondition cond = IndexCondition.get( |
324 | Comparison.EQUAL, this, ValueExpression.get( |
325 | ValueBoolean.get(true))); |
326 | filter.addIndexCondition(cond); |
327 | } |
328 | } |
329 | |
330 | @Override |
331 | public Expression getNotIfPossible(Session session) { |
332 | return new Comparison(session, Comparison.EQUAL, this, |
333 | ValueExpression.get(ValueBoolean.get(false))); |
334 | } |
335 | |
336 | } |