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1 package com.quadcap.sql;
2
3
40
41 import java.io.ByteArrayOutputStream  ;
42 import java.io.Externalizable ;
43 import java.io.IOException ;
44 import java.io.ObjectInput ;
45 import java.io.ObjectOutput ;
46
47 import java.util.Vector ;
48
49 import java.sql.SQLException ;
50
51 import com.quadcap.sql.io.ObjectInputStream;
52 import com.quadcap.sql.io.ObjectOutputStream;
53
54 import com.quadcap.sql.file.BlockFile;
55
56 import com.quadcap.sql.types.Op;
57 import com.quadcap.sql.types.Type;
58 import com.quadcap.sql.types.Value;
59
60 import com.quadcap.util.Debug;
61 import com.quadcap.util.Util;
62
63
69 public class MergeExpression extends TableExpression
70 implements Externalizable
71 {
72 int op;
73 boolean all;
74 boolean corr;
75 TableExpression a;
76 TableExpression b;
77 Vector columns;
78 TempTableMerge tempTable;
79 MergeCursor mcursor = null;
80 int[] amap = null;
81 int[] bmap = null;
82 Type[] typeMap = null;
83
84 public MergeExpression() {}
85
86 public MergeExpression(int op, boolean all, TableExpression a,
87 TableExpression b, Vector columns,
88 boolean corr) {
89 this.op = op;
90 this.all = all;
91 this.a = a;
92 this.b = b;
93 this.columns = columns;
94 this.corr = corr;
95 }
96
97 public int rank() { return 2; }
98
99 public boolean isUpdatable() { return false; }
100
101 public void getBaseTables(Vector v) {
102 a.getBaseTables(v);
103 b.getBaseTables(v);
104 }
105
106 public void setWhere(Expression where) {
107 this.where = where;
108 a.setWhere(where);
109 b.setWhere(where);
110 }
111
112 public Cursor getCursor(Session session, Cursor c) throws SQLException {
113 try {
114 Cursor ca = a.getCursor(session, c);
115 Cursor cb = b.getCursor(session, c);
116
117 try {
118 checkCorresponding(ca, cb);
119
120 Key compare = new Key(amap.length);
121
122 tempTable = new TempTableMerge(session, compare);
123 tempTable.addRows(session, ca, 0, amap);
124 tempTable.addRows(session, cb, 1, bmap);
125
126 mcursor = new MergeCursor(session, op, all, tempTable);
127
128 if (!corr) {
129 for (int i = 1; i <= ca.getColumnCount(); i++) {
130 Column col = ca.getColumn(i);
131 mcursor.addColumn(new Column(col.getName(), col));
132 }
133 } else {
134 for (int i = 0; i < amap.length; i++) {
135 Column col = ca.getColumn(amap[i]);
136 mcursor.addColumn(new Column(col.getName(), col));
137 }
138 }
139 mcursor.resolveColumns();
140 } finally {
141 ca.close();
142 cb.close();
143 }
144 } catch (IOException e) {
145 throw DbException.wrapThrowable(e);
146 }
147 return mcursor;
148 }
149
150 void checkCorresponding(Cursor ca, Cursor cb) throws SQLException {
151 if (!corr) {
152 if (ca.getColumnCount() != cb.getColumnCount()) {
153 throw new SQLException (Op.toString(op) + " merge " +
154 "operation, tables must have the " +
155 "same number of columns", "42000");
156 }
157 amap = new int[ca.getColumnCount()];
158 bmap = new int[amap.length];
159 for (int i = 0; i < amap.length; i++) {
160 amap[i] = bmap[i] = i+1;
161 }
162 } else if (columns == null) {
163 int cnt = 0;
165 for (int i = 1; i <= ca.getColumnCount(); i++) {
166 Column cola = ca.getColumn(i);
167 Column colb = cb.getColumn(cola.getShortName());
168 if (colb != null) {
169 cnt++;
170 }
171 }
172 if (cnt == 0) {
173 throw new SQLException (Op.toString(op) + " CORRESPONDING, " +
174 "no common columns found", "42000");
175 }
176 amap = new int[cnt];
177 bmap = new int[cnt];
178 int p = 0;
179 for (int i = 1; i <= ca.getColumnCount(); i++) {
180 Column cola = ca.getColumn(i);
181 Column colb = cb.getColumn(cola.getShortName());
182 if (colb != null) {
183 amap[p] = cola.getColumn();
184 bmap[p] = colb.getColumn();
185 p++;
186 }
187 }
188 } else {
189 amap = new int[columns.size()];
190 bmap = new int[amap.length];
191
192 for (int i = 0; i < columns.size(); i++) {
193 String name = (String )columns.elementAt(i);
194 Column cola = ca.getColumn(name);
195 if (cola == null) {
196 throw new SQLException ("Not found: " + name, "42000");
197 }
198 amap[i] = cola.getColumn();
199
200 Column colb = cb.getColumn(name);
201 if (colb == null) {
202 throw new SQLException ("Not found: " + name, "42000");
203 }
204 bmap[i] = colb.getColumn();
205 }
206 }
207 }
208
209 public void invert() {
210 throw new RuntimeException (
211 "invert not implemented for MergeExpression");
212 }
213
214 public void readExternal(ObjectInput in)
215 throws IOException , ClassNotFoundException
216 {
217 this.op = in.read();
218 this.all = in.read() == 1;
219 this.a = (TableExpression)in.readObject();
220 this.b = (TableExpression)in.readObject();
221 this.columns = (Vector )in.readObject();
222 this.corr = in.read() == 1;
223 }
224
225 public void writeExternal(ObjectOutput out) throws IOException {
226 out.write(op);
227 out.write(all ? 1 : 0);
228 out.writeObject(a);
229 out.writeObject(b);
230 out.writeObject(columns);
231 out.write(corr ? 1 : 0);
232 }
233
234 public void visitSubExpressions(ExpressionVisitor ev) {
235 ev.visit(a);
236 ev.visit(b);
237 }
238
239 public String toString() {
240 StringBuffer sb = new StringBuffer (a.toString());
241 sb.append(' ');
242 sb.append(Op.toString(op));
243 if (all) sb.append(" ALL");
244 if (corr) {
245 sb.append(" CORRESPONDING");
246 if (columns != null) {
247 sb.append(" BY (");
248 for (int i = 0; i < columns.size(); i++) {
249 if (i > 0) sb.append(',');
250 sb.append(columns.get(i).toString());
251 }
252 sb.append(")");
253 }
254 }
255 sb.append(' ');
256 sb.append(b.toString());
257 return sb.toString();
258 }
259
260 public String name() {
262 StringBuffer sb = new StringBuffer ('(');
263 sb.append(a.name());
264 sb.append(' ');
265 sb.append(Op.toString(op));
266 sb.append(' ');
267 sb.append(b.name());
268 sb.append(')');
269 return sb.toString();
270 }
271 }
273 |
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