Merge pull request #3986 from katzyn/cte

Move CTEs to their own scope of identifiers
h2database · Jan 28, 2024 · 494bd66 · 494bd66
2 parents d2c2b32 + bad447b
commit 494bd66
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Showing 39 changed files with 356 additions and 589 deletions.
diff --git a/h2/src/docsrc/html/changelog.html b/h2/src/docsrc/html/changelog.html
@@ -21,6 +21,8 @@ <h1>Change Log</h1>
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #910: Common Table Expressions (CTE) inside WITH should have their own identifier scope
+</li>
 <li>Issue #3981: Unexpected result when using trigonometric functions
 </li>
 <li>Issue #3983: INVISIBLE columns should be ignored in INSERT statement without explicit column list

diff --git a/h2/src/main/org/h2/command/CommandContainer.java b/h2/src/main/org/h2/command/CommandContainer.java
@@ -7,8 +7,8 @@
 
 import java.util.ArrayList;
 import java.util.HashSet;
-import java.util.List;
 import java.util.Set;
+
 import org.h2.api.DatabaseEventListener;
 import org.h2.api.ErrorCode;
 import org.h2.command.dml.DataChangeStatement;
@@ -29,7 +29,6 @@
 import org.h2.table.Column;
 import org.h2.table.DataChangeDeltaTable.ResultOption;
 import org.h2.table.Table;
-import org.h2.table.TableView;
 import org.h2.util.StringUtils;
 import org.h2.util.Utils;
 import org.h2.value.Value;
@@ -80,35 +79,6 @@ public void addRow(Value... values) {
     private boolean readOnlyKnown;
     private boolean readOnly;
 
-    /**
-     * Clears CTE views for a specified statement.
-     *
-     * @param session the session
-     * @param prepared prepared statement
-     */
-    static void clearCTE(SessionLocal session, Prepared prepared) {
-        List<TableView> cteCleanups = prepared.getCteCleanups();
-        if (cteCleanups != null) {
-            clearCTE(session, cteCleanups);
-        }
-    }
-
-    /**
-     * Clears CTE views.
-     *
-     * @param session the session
-     * @param views list of view
-     */
-    static void clearCTE(SessionLocal session, List<TableView> views) {
-        for (TableView view : views) {
-            // check if view was previously deleted as their name is set to
-            // null
-            if (view.getName() != null) {
-                session.removeLocalTempTable(view);
-            }
-        }
-    }
-
     public CommandContainer(SessionLocal session, String sql, Prepared prepared) {
         super(session, sql);
         prepared.setCommand(this);
@@ -255,19 +225,6 @@ public ResultInterface query(long maxrows) {
         return result;
     }
 
-    @Override
-    public void stop() {
-        super.stop();
-        // Clean up after the command was run in the session.
-        // Must restart query (and dependency construction) to reuse.
-        clearCTE(session, prepared);
-    }
-
-    @Override
-    public boolean canReuse() {
-        return super.canReuse() && prepared.getCteCleanups() == null;
-    }
-
     @Override
     public boolean isReadOnly() {
         if (!readOnlyKnown) {
@@ -292,13 +249,6 @@ public int getCommandType() {
         return prepared.getType();
     }
 
-    /**
-     * Clean up any associated CTE.
-     */
-    void clearCTE() {
-        clearCTE(session, prepared);
-    }
-
     @Override
     public Set<DbObject> getDependencies() {
         HashSet<DbObject> dependencies = new HashSet<>();

diff --git a/h2/src/main/org/h2/command/CommandList.java b/h2/src/main/org/h2/command/CommandList.java
@@ -77,9 +77,6 @@ public ResultInterface query(long maxrows) {
     @Override
     public void stop() {
         command.stop();
-        for (Prepared prepared : commands) {
-            CommandContainer.clearCTE(session, prepared);
-        }
         if (remainingCommand != null) {
             remainingCommand.stop();
         }