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1
5 package org.h2.command.dml;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.command.Prepared;
10 import org.h2.engine.Right;
11 import org.h2.engine.Session;
12 import org.h2.expression.Expression;
13 import org.h2.result.Row;
14 import org.h2.store.UndoLogRecord;
15 import org.h2.table.PlanItem;
16 import org.h2.table.Table;
17 import org.h2.table.TableFilter;
18 import org.h2.util.ObjectArray;
19 import org.h2.util.StringUtils;
20
21
24 public class Delete extends Prepared {
25
26 private Expression condition;
27 private TableFilter tableFilter;
28
29 public Delete(Session session) {
30 super(session);
31 }
32
33 public void setTableFilter(TableFilter tableFilter) {
34 this.tableFilter = tableFilter;
35 }
36
37 public void setCondition(Expression condition) {
38 this.condition = condition;
39 }
40
41 public int update() throws SQLException {
42 tableFilter.startQuery();
43 tableFilter.reset();
44 Table table = tableFilter.getTable();
45 session.getUser().checkRight(table, Right.DELETE);
46 table.fireBefore(session);
47 table.lock(session, true);
48 ObjectArray rows = new ObjectArray();
49 setCurrentRowNumber(0);
50 while (tableFilter.next()) {
51 checkCancelled();
52 setCurrentRowNumber(rows.size()+1);
53 if (condition == null || Boolean.TRUE.equals(condition.getBooleanValue(session))) {
54 Row row = tableFilter.get();
55 rows.add(row);
56 }
57 }
58 if(table.fireRow()) {
59 for (int i = 0; i < rows.size(); i++) {
60 checkCancelled();
61 Row row = (Row) rows.get(i);
62 table.fireBeforeRow(session, row, null);
63 }
64 }
65 for (int i = 0; i < rows.size(); i++) {
66 checkCancelled();
67 Row row = (Row) rows.get(i);
68 table.removeRow(session, row);
69 session.log(new UndoLogRecord(table, UndoLogRecord.DELETE, row));
70 }
71 if(table.fireRow()) {
72 for (int i = 0; i < rows.size(); i++) {
73 checkCancelled();
74 Row row = (Row) rows.get(i);
75 table.fireAfterRow(session, row, null);
76 }
77 }
78 table.fireAfter(session);
79 return rows.size();
80 }
81
82 public String getPlan() {
83 StringBuffer buff = new StringBuffer ();
84 buff.append("DELETE FROM ");
85 buff.append(tableFilter.getPlanSQL(false));
86 if(condition != null) {
87 buff.append("\nWHERE " + StringUtils.unEnclose(condition.getSQL()));
88 }
89 return buff.toString();
90 }
91
92 public void prepare() throws SQLException {
93 if (condition != null) {
94 condition.mapColumns(tableFilter, 0);
95 condition = condition.optimize(session);
96 condition.createIndexConditions(tableFilter);
97 }
98 PlanItem item = tableFilter.getBestPlanItem(session);
99 tableFilter.setPlanItem(item);
100 tableFilter.prepare();
101 }
102
103 public boolean isTransactional() {
104 return true;
105 }
106
107 }
108 |
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