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1 package com.quadcap.sql;
2
3
40
41 import java.io.Externalizable  ;
42 import java.io.IOException ;
43 import java.io.ObjectInput ;
44 import java.io.ObjectOutput ;
45
46 import java.util.Hashtable ;
47 import java.util.Vector ;
48
49 import java.sql.ResultSetMetaData ;
50 import java.sql.SQLException ;
51
52 import com.quadcap.sql.index.Btree;
53
54 import com.quadcap.sql.types.Value;
55 import com.quadcap.sql.types.ValueBoolean;
56
57 import com.quadcap.util.Debug;
58
59
64 public class View extends TupleImpl implements Relation, Externalizable {
65 Vector viewColumns;
66 TableExpression select;
67
68 static final int NOCHECK = -1;
69 static final int CASCADED = 0;
70 static final int LOCAL = 1;
71
72 int check;
73
74
77 public View() {}
78
79
83 public View(String name, Vector columns, TableExpression select,
84 int check)
85 {
86 super(name);
87 this.viewColumns = columns;
88 this.select = select;
89 this.check = check;
90 }
91
92
95 public void addColumns(Session session) throws SQLException {
96 if (columns.size() == 0) {
97 Cursor c = getCursor(session, null, null, null);
98 try {
99 addColumns(session, c);
100 } finally {
101 c.close();
102 }
103 }
104 }
105
106
109 public void checkRow(Session session, Cursor cursor, Row row) throws SQLException {
110 if ((check != NOCHECK || session.getViewCheck())
111 && select.isUpdatable()) {
112 session.setViewCheck();
113 StaticCursor s = new StaticCursor(session, this, row);
114 s.next();
115 Expression w = select.getWhere();
116 if (w != null) {
117 Value v = w.getValue(session, s);
118 if (v instanceof ValueBoolean && ((ValueBoolean)v).isTrue()) {
119 } else {
121 throw new SQLException ("View check option violation", "44000");
122 }
123 }
124 }
125 }
126
127
130 public void readExternal(ObjectInput in)
131 throws IOException , ClassNotFoundException
132 {
133 super.readExternal(in);
134 this.viewColumns = (Vector )in.readObject();
135 this.select = (TableExpression)in.readObject();
136 this.check = in.readInt();
137 }
138
139
142 public void writeExternal(ObjectOutput out) throws IOException {
143 super.writeExternal(out);
144 out.writeObject(viewColumns);
145 out.writeObject(select);
146 out.writeInt(check);
147 }
148
149
152 public Cursor getCursor(Session session, Expression where,
153 String asName, Cursor cursor)
154 throws SQLException
155 {
156 Cursor c = select.getCursor(session, cursor);
157
158 String qualName = asName;
159 if (qualName == null) qualName = getName();
160 String qPrefix = qualName;
161 if (qPrefix.length() > 0) qPrefix = qPrefix + ".";
162
163 Vector cols = viewColumns;
164 if (cols == null) {
165 cols = new Vector ();
166 Hashtable t = new Hashtable ();
167 for (int i = 1; i <= c.getColumnCount(); i++) {
168 String name = c.getColumn(i).getName();
169 int idx = name.lastIndexOf('.');
170 if (idx >= 0) name = name.substring(idx+1);
171 name = qPrefix + name;
172 if (t.get(name) != null) {
173 throw new SQLException (
174 "A view column list must be specified if multiple " +
175 "columns have the same name: " + name, "42000");
176 }
177 cols.addElement(name);
178 t.put(name, name);
179 }
180 } else {
181 cols = new Vector ();
182 for (int i = 0; i < viewColumns.size(); i++) {
183 cols.addElement(qPrefix + viewColumns.elementAt(i).toString());
184 }
185 }
186 c = new ViewCursor(session, this, c, cols);
187 return c;
188 }
189
190 public void insertRow(Session session, Row row)
191 throws SQLException , IOException
192 {
193 Cursor c = getCursor(session, null, null, null);
194 try {
195 session.clearViewCheck();
196 c.insertRow(row);
197 } finally {
198 c.close();
199 }
200 }
201
202 public boolean isUpdatable() {
203 return select.isUpdatable();
204 }
205
206 public boolean hasBlobs() {
207 return false; }
209
210 public Vector getBaseTables() {
211 Vector v = new Vector ();
212 select.getBaseTables(v);
213 return v;
214 }
215
216 public Expression getViewExpression() {
217 return select;
218 }
219
220 public String getType() { return "VIEW"; }
221
222 public void delete(Session session) {}
223
224 public String toString() {
225 StringBuffer sb = new StringBuffer ("VIEW ");
226 sb.append(getName());
227 if (columns != null) {
228 sb.append('(');
229 for (int i = 0; i < columns.size(); i++) {
230 if (i > 0) sb.append(',');
231 Column col = (Column)columns.get(i);
232 sb.append(col.getShortName());
233 }
234 sb.append(')');
235 }
236 sb.append(" AS ");
237 sb.append(select.toString());
238 return sb.toString();
239 }
240
241 }
242 |
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