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1
5 package org.h2.expression;
6
7 import java.sql.SQLException  ;
8
9 import org.h2.command.Prepared;
10 import org.h2.engine.Session;
11 import org.h2.message.Message;
12 import org.h2.table.ColumnResolver;
13 import org.h2.table.TableFilter;
14 import org.h2.value.Value;
15 import org.h2.value.ValueInt;
16
17 public class Rownum extends Expression {
18
19 private Prepared prepared;
20
21 public Rownum(Prepared prepared) {
22 this.prepared = prepared;
23 }
24
25 public Value getValue(Session session) throws SQLException {
26 return ValueInt.get(prepared.getCurrentRowNumber());
27 }
28
29 public int getType() {
30 return Value.INT;
31 }
32
33 public void mapColumns(ColumnResolver resolver, int level) throws SQLException {
34 }
35
36 public Expression optimize(Session session) throws SQLException {
37 return this;
38 }
39
40 public void setEvaluatable(TableFilter tableFilter, boolean b) {
41 }
42
43 public int getScale() {
44 return 0;
45 }
46
47 public long getPrecision() {
48 return ValueInt.PRECISION;
49 }
50
51 public String getSQL() {
52 return "ROWNUM()";
53 }
54
55 public void updateAggregate(Session session) throws SQLException {
56 }
57
58 public boolean isEverything(ExpressionVisitor visitor) {
59 switch(visitor.type) {
60 case ExpressionVisitor.OPTIMIZABLE_MIN_MAX_COUNT_ALL:
61 return false;
62 case ExpressionVisitor.DETERMINISTIC:
63 return false;
64 case ExpressionVisitor.INDEPENDENT:
65 return false;
66 case ExpressionVisitor.EVALUATABLE:
67 return true;
68 case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID:
69 return true;
71 case ExpressionVisitor.READONLY:
72 return true;
73 default:
74 throw Message.getInternalError("type="+visitor.type);
75 }
76 }
77
78 public int getCost() {
79 return 0;
80 }
81
82 }
83 |
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