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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.ArrayList ;
47 import java.util.Enumeration ;
48 import java.util.HashMap ;
49 import java.util.Iterator ;
50 import java.util.Map ;
51
52 import java.sql.SQLException ;
53
54 import com.quadcap.sql.file.BlockFile;
55 import com.quadcap.sql.file.ByteUtil;
56
57 import com.quadcap.sql.index.Btree;
58 import com.quadcap.sql.index.BCursor;
59
60 import com.quadcap.sql.io.Extern;
61
62 import com.quadcap.util.Debug;
63
64
69
70 public class StmtRenameTable extends LogStep implements Stmt, Externalizable {
71 String oldName;
72 String newName;
73 Relation r;
74
75 public StmtRenameTable() {}
76
77 public StmtRenameTable(String oldName, String newName) {
78 this.oldName = oldName;
79 this.newName = newName;
80 }
81
82 public void execute(Session session) throws IOException , SQLException {
83 session.getTableWriteLock("#Schema");
84 session.getTableWriteLock(oldName);
85 session.getTableWriteLock(newName);
86 session.doStep(this);
87 }
88
89 public void redo(Session session) throws IOException , SQLException {
90 rename(session, oldName, newName);
91 }
92
93 public void undo(Session session) throws IOException , SQLException {
94 rename(session, newName, oldName);
95 }
96
97 public void rename(Session session, String oldN, String newN)
98 throws IOException , SQLException
99 {
100 Database db = session.getDatabase();
101 Relation oldR = db.getRelation(oldN);
102 if (oldR == null) {
103 throw new SQLException ("no such table: " + oldN, "42000");
104 }
105 db.renameRelation(oldR, newN);
106 Relation newR = db.getRelation(newN);
107 if (newR == null) {
108 throw new SQLException ("rename failed!: " + newN);
109 }
110
111 Enumeration views = db.getViews(newN);
112 while (views.hasMoreElements()) {
113 String view1 = views.nextElement().toString();
114 renameView(session, view1, oldN, newN);
115 }
116
117 if (newR instanceof Table) {
118 Map referencingTables = new HashMap ();
119 Table t = (Table)newR;
120 int num = t.getNumConstraints();
121 for (int i = 0; i < num; i++) {
122 Constraint c = t.getConstraint(i);
123 if (c instanceof ForeignKeyConstraint) {
124 ForeignKeyConstraint fc = (ForeignKeyConstraint)c;
125 String fTable = fc.getFTableName();
126 referencingTables.put(fTable, "");
127 }
128 }
129 if (referencingTables.size() > 0) {
130 Iterator iter = referencingTables.keySet().iterator();
131 while (iter.hasNext()) {
132 renameForeignKeys(session, iter.next().toString(), oldN, newN);
133 }
134 db.updateRelation(newR);
135 }
136 }
137 }
138
139 void renameForeignKeys(Session session, String tableName, String oldN,
140 String newN)
141 throws IOException , SQLException
142 {
143 session.getTableReadLock(tableName);
144 Database db = session.getDatabase();
145 Table t = (Table)db.getRelation(tableName);
146 int num = t.getNumConstraints();
147 for (int i = 0; i < num; i++) {
148 Constraint c = t.getConstraint(i);
149 if (c instanceof ForeignKeyConstraint) {
150 ForeignKeyConstraint fc = (ForeignKeyConstraint)c;
151 String fTable = fc.getFTableName();
152 if (fTable.equals(oldN)) {
153 fc.setFTableName(newN);
154 fc.resetColumns();
155 }
156 }
157 }
158 db.updateRelation(t);
159 }
160
161 class RenameTableVisitor implements ExpressionVisitor {
162 String oldN;
163 String newN;
164 RenameTableVisitor(String oldN, String newN) {
165 this.oldN = oldN;
166 this.newN = newN;
167 }
168 public void visit(Expression ex) {
169 if (ex instanceof SelectFromTable) {
170 SelectFromTable sf = (SelectFromTable)ex;
171 String tableName = sf.getTableName();
172 if (tableName.equals(oldN)) {
173 sf.setTableName(newN);
174 }
175 } else if (ex instanceof SelectExpression) {
176 Iterator iter = ((SelectExpression)ex).getFrom().iterator();
177 while (iter.hasNext()) {
178 visit((Expression)iter.next());
179 }
180 }
181 ex.visitSubExpressions(this);
182 }
183 }
184
185 void renameView(Session session, String viewName, String oldN,
186 String newN)
187 throws IOException , SQLException
188 {
189
190 session.getTableReadLock(viewName);
191
192 Database db = session.getDatabase();
193 View v = (View)db.getRelation(viewName);
194 Expression viewEx = v.getViewExpression();
195 RenameTableVisitor visitor = new RenameTableVisitor(oldN, newN);
196 visitor.visit(viewEx);
197 db.updateRelation(v);
198 }
199
200 public void prepare(Session session) throws IOException , SQLException {
201 }
202
203 public void readExternal(ObjectInput in)
204 throws IOException , ClassNotFoundException
205 {
206 oldName = (String )in.readObject();
207 newName = (String )in.readObject();
208 }
209
210 public void writeExternal(ObjectOutput out) throws IOException {
211 out.writeObject(oldName);
212 out.writeObject(newName);
213 }
214
215
219 public String toString() {
220 StringBuffer sb = new StringBuffer (super.toString());
221 sb.append(" RenameTable(");
222 sb.append(oldName);
223 sb.append(" to ");
224 sb.append(newName);
225 sb.append(')');
226 return sb.toString();
227 }
228
230 static Extern extern;
231 public void setExtern(Extern extern) { StmtRenameTable.extern = extern; }
232 public Extern getExtern() { return extern; }
233 }
234 |
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