For alias columns, ResultSetMetaData.getTableName() and getColumnName() now…

For alias columns, ResultSetMetaData.getTableName() and getColumnName() now return the real table and column name.

h2/src/main/org/h2/command/Parser.java

@@ -1555,7 +1555,7 @@ public class Parser {
                 Expression expr = readExpression();
                 if (readIf("AS") || currentTokenType == IDENTIFIER) {
                     String alias = readAliasIdentifier();
-                    expr = new Alias(expr, alias);
+                    expr = new Alias(expr, alias, database.getMode().aliasColumnName);
                 }
                 expressions.add(expr);
             }

h2/src/main/org/h2/command/ddl/CreateTable.java

@@ -115,7 +115,7 @@ public class CreateTable extends SchemaCommand {
         if (asQuery != null) {
             asQuery.prepare();
             if (columns.size() == 0) {
-                generateColumnFromQuery();
+                generateColumnsFromQuery();
             } else if (columns.size() != asQuery.getColumnCount()) {
                 throw Message.getSQLException(ErrorCode.COLUMN_COUNT_DOES_NOT_MATCH);
             }
@@ -194,13 +194,13 @@ public class CreateTable extends SchemaCommand {
         return 0;
     }
 
-    private void generateColumnFromQuery() {
+    private void generateColumnsFromQuery() {
         int columnCount = asQuery.getColumnCount();
         ObjectArray expressions = asQuery.getExpressions();
         for (int i = 0; i < columnCount; i++) {
             Expression expr = (Expression) expressions.get(i);
             int type = expr.getType();
-            String name = expr.getColumnName();
+            String name = expr.getAlias();
             long precision = expr.getPrecision();
             int displaySize = expr.getDisplaySize();
             DataType dt = DataType.getDataType(type);

h2/src/main/org/h2/command/dml/Select.java

@@ -13,6 +13,7 @@ import java.util.HashSet;
 import org.h2.constant.ErrorCode;
 import org.h2.constant.SysProperties;
 import org.h2.engine.Constants;
+import org.h2.engine.Mode;
 import org.h2.engine.Session;
 import org.h2.expression.Alias;
 import org.h2.expression.Comparison;
@@ -1089,7 +1090,8 @@ public class Select extends Query {
         if (expr instanceof Alias) {
             return expr.getAlias();
         }
-        expr = new Alias(expr,  session.getNextTempViewName() + "_X");
+        Mode mode = session.getDatabase().getMode();
+        expr = new Alias(expr,  session.getNextTempViewName() + "_X", mode.aliasColumnName);
         expressions.set(0, expr);
         return expr.getAlias();
     }

h2/src/main/org/h2/constant/SysProperties.java

@@ -72,16 +72,23 @@ public class SysProperties {
     public static final String USER_HOME = getStringSetting("user.home", "");
 
     /**
-     * System property <code>h2.aliasColumnName</code> (default: false).<br />
+     * System property <code>h2.aliasColumnName</code>.<br />
      * When enabled, aliased columns (as in SELECT ID AS I FROM TEST) return the
-     * real table and column name in ResultSetMetaData.getTableName() and
-     * getColumnName().
+     * alias (I in this case) in ResultSetMetaData.getColumnName() and 'null' in
+     * getTableName(). If disabled, the real column name (ID in this case) and
+     * table name is returned. This setting only affects the default mode.
      * <p>
-     * This feature is disabled by default for compatibility with other
-     * databases (HSQLDB, Apache Derby, PostgreSQL, some version of MySQL).
+     * When using different modes, this feature is disabled for compatibility
+     * for all databases except MySQL. For MySQL, it is always enabled.
+     * </p>
+     * <p>
+     * In version 1.0, it is enabled by default.
+     * </p>
+     * <p>
+     * In version 1.1, it is disabled by default.
      * </p>
      */
-    public static final boolean ALIAS_COLUMN_NAME = getBooleanSetting("h2.aliasColumnName", false);
+    public static final boolean ALIAS_COLUMN_NAME = getBooleanSetting("h2.aliasColumnName", Constants.VERSION <= 1.0);
 
     /**
      * System property <code>h2.allowBigDecimalExtensions</code> (default:
@@ -164,10 +171,10 @@ public class SysProperties {
     public static final int DATASOURCE_TRACE_LEVEL = getIntSetting("h2.dataSourceTraceLevel", TraceSystem.ERROR);
 
     /**
-     * System property <code>h2.defaultMaxMemoryUndo</code> (default: 100000).<br />
+     * System property <code>h2.defaultMaxMemoryUndo</code> (default: 50000).<br />
      * The default value for the MAX_MEMORY_UNDO setting.
      */
-    public static final int DEFAULT_MAX_MEMORY_UNDO = getIntSetting("h2.defaultMaxMemoryUndo", 100000);
+    public static final int DEFAULT_MAX_MEMORY_UNDO = getIntSetting("h2.defaultMaxMemoryUndo", 50000);
 
     /**
      * System property <code>h2.defaultLockMode</code> (default: 3).<br />

h2/src/main/org/h2/expression/Alias.java

@@ -9,7 +9,6 @@ package org.h2.expression;
 import java.sql.SQLException;
 
 import org.h2.command.Parser;
-import org.h2.constant.SysProperties;
 import org.h2.engine.Session;
 import org.h2.table.ColumnResolver;
 import org.h2.table.TableFilter;
@@ -22,10 +21,12 @@ public class Alias extends Expression {
 
     private final String alias;
     private Expression expr;
+    private boolean aliasColumnName;
 
-    public Alias(Expression expression, String alias) {
+    public Alias(Expression expression, String alias, boolean aliasColumnName) {
         this.expr = expression;
         this.alias = alias;
+        this.aliasColumnName = aliasColumnName;
     }
 
     public Expression getNonAliasExpression() {
@@ -94,17 +95,17 @@ public class Alias extends Expression {
     }
     
     public String getTableName() {
-        if (SysProperties.ALIAS_COLUMN_NAME) {
-            return expr.getTableName();
+        if (aliasColumnName) {
+            return super.getTableName();
         }
-        return super.getTableName();
+        return expr.getTableName();
     }
 
     public String getColumnName() {
-        if (SysProperties.ALIAS_COLUMN_NAME) {
-            return expr.getColumnName();
+        if (aliasColumnName) {
+            return super.getColumnName();
         }
-        return super.getColumnName();
+        return expr.getColumnName();
     }
 
 }

h2/src/main/org/h2/expression/Function.java

@@ -922,13 +922,13 @@ public class Function extends Expression implements FunctionCall {
             result = ValueString.get(right(v0.getString(), v1.getInt()));
             break;
         case LTRIM:
-            result = ValueString.get(trim(v0.getString(), true, false, v1 == null ? " " : v1.getString()));
+            result = ValueString.get(StringUtils.trim(v0.getString(), true, false, v1 == null ? " " : v1.getString()));
             break;
         case TRIM:
-            result = ValueString.get(trim(v0.getString(), true, true, v1 == null ? " " : v1.getString()));
+            result = ValueString.get(StringUtils.trim(v0.getString(), true, true, v1 == null ? " " : v1.getString()));
             break;
         case RTRIM:
-            result = ValueString.get(trim(v0.getString(), false, true, v1 == null ? " " : v1.getString()));
+            result = ValueString.get(StringUtils.trim(v0.getString(), false, true, v1 == null ? " " : v1.getString()));
             break;
         case SUBSTR:
         case SUBSTRING: {
@@ -1242,28 +1242,6 @@ public class Function extends Expression implements FunctionCall {
         return s.substring(start, start + length);
     }
 
-    private static String trim(String s, boolean leading, boolean trailing, String sp) {
-        char space = (sp == null || sp.length() < 1) ? ' ' : sp.charAt(0);
-        // TODO function trim: HSQLDB says 'tabs are not removed', but they are.
-        // check what other databases do
-        if (leading) {
-            int len = s.length(), i = 0;
-            while (i < len && s.charAt(i) == space) {
-                i++;
-            }
-            s = (i == 0) ? s : s.substring(i);
-        }
-        if (trailing) {
-            int endIndex = s.length() - 1;
-            int i = endIndex;
-            while (i >= 0 && s.charAt(i) == space) {
-                i--;
-            }
-            s = i == endIndex ? s : s.substring(0, i + 1);
-        }
-        return s;
-    }
-
     private static String replace(String s, String replace, String with) {
         if (replace == null || replace.length() == 0) {
             // avoid out of memory

h2/src/main/org/h2/util/StringUtils.java

@@ -861,5 +861,37 @@ public class StringUtils {
         System.arraycopy(chars, 0, copy, 0, len);
         return copy;
     }
+    
+    /**
+     * Trim a character from a string.
+     * 
+     * @param s the string
+     * @param leading if leading characters should be removed
+     * @param trailing if trailing characters should be removed
+     * @param sp what to remove (only the first character is used) 
+     *      or null for a space
+     * @return the trimmed string
+     */
+    public static String trim(String s, boolean leading, boolean trailing, String sp) {
+        char space = (sp == null || sp.length() < 1) ? ' ' : sp.charAt(0);
+        // TODO function trim: HSQLDB says 'tabs are not removed', but they are.
+        // check what other databases do
+        if (leading) {
+            int len = s.length(), i = 0;
+            while (i < len && s.charAt(i) == space) {
+                i++;
+            }
+            s = (i == 0) ? s : s.substring(i);
+        }
+        if (trailing) {
+            int endIndex = s.length() - 1;
+            int i = endIndex;
+            while (i >= 0 && s.charAt(i) == space) {
+                i--;
+            }
+            s = i == endIndex ? s : s.substring(0, i + 1);
+        }
+        return s;
+    }
 
 }