Merge pull request #1745 from katzyn/lower

Add DATABASE_TO_LOWER and CASE_INSENSITIVE_IDENTIFIERS

h2/src/docsrc/help/help.csv

@@ -2797,7 +2797,7 @@ CURRENT ROW
 
 "Other Grammar","Term","
 value
-    | columnName
+    | column
     | ?[ int ]
     | NEXT VALUE FOR sequenceName
     | function
@@ -2806,15 +2806,22 @@ value
     | select
     | case
     | caseWhen
-    | tableAlias.columnName
     | userDefinedFunctionName
 ","
 A value. Parameters can be indexed, for example ""?1"" meaning the first parameter.
-Each table has a pseudo-column named ""_ROWID_"" that contains the unique row identifier.
 ","
 'Hello'
 "
 
+"Other Grammar","Column","
+[[schemaName.]tableAlias.] { columnName | _ROWID_ }
+","
+A column name with optional table alias and schema.
+_ROWID_ can be used to access unique row identifier.
+","
+ID
+"
+
 "Other Grammar","Time","
 TIME [ WITHOUT TIME ZONE ] 'hh:mm:ss[.nnnnnnnnn]'
 ","

h2/src/docsrc/html/advanced.html

@@ -480,7 +480,7 @@ CURRENT_TIME, CURRENT_TIMESTAMP, CURRENT_USER, DISTINCT, EXCEPT,
 EXISTS, FALSE, FETCH, FOR, FOREIGN, FROM, FULL, GROUP, HAVING,
 IF, INNER, INTERSECT, INTERSECTS, INTERVAL, IS, JOIN, LIKE,
 LIMIT, LOCALTIME, LOCALTIMESTAMP, MINUS, NATURAL, NOT, NULL,
-OFFSET, ON, ORDER, PRIMARY, QUALIFY, ROW, ROWNUM, SELECT,
+OFFSET, ON, ORDER, PRIMARY, QUALIFY, ROW, _ROWID_, ROWNUM, SELECT,
 SYSDATE, SYSTIME, SYSTIMESTAMP, TABLE, TODAY, TOP, TRUE, UNION,
 UNIQUE, VALUES, WHERE, WINDOW, WITH
 </code>

h2/src/docsrc/html/changelog.html

@@ -21,6 +21,18 @@ Change Log
 
 <h2>Next Version (unreleased)</h2>
 <ul>
+<li>Issue #1739: Table and view names not case sensitive when using DATABASE_TO_UPPER=FALSE
+</li>
+<li>Issue #848: H2 PostgreSQL Compatibility Mode: lowercase metadata
+</li>
+<li>Issue #485: Problem is in invalid case for schema's IGNORECASE=true;DATABASE_TO_UPPER=false
+</li>
+<li>Issue #1742, PR #1743: Assorted small changes
+</li>
+<li>PR #1738: Reduce memory allocation in getSQL() methods
+</li>
+<li>PR #1737: more javadoc updates
+</li>
 <li>Issue #1735: Creating views with DATABASE_TO_UPPER=FALSE fails
 </li>
 <li>Issue #1732: source.html does not work

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

@@ -107,7 +107,7 @@ public class AlterTableAddConstraint extends SchemaCommand {
             }
             throw DbException.get(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, tableName);
         }
-        if (getSchema().findConstraint(session, constraintName) != null) {
+        if (constraintName != null && getSchema().findConstraint(session, constraintName) != null) {
             if (ifNotExists) {
                 return 0;
             }

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

@@ -69,7 +69,7 @@ public class CreateIndex extends SchemaCommand {
             }
             throw DbException.get(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, tableName);
         }
-        if (getSchema().findIndex(session, indexName) != null) {
+        if (indexName != null && getSchema().findIndex(session, indexName) != null) {
             if (ifNotExists) {
                 return 0;
             }

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

@@ -459,7 +459,7 @@ public class Insert extends CommandWithValues implements ResultTarget {
         for (Column column : indexedColumns) {
             ExpressionColumn expr = new ExpressionColumn(session.getDatabase(),
                     table.getSchema().getName(), table.getName(),
-                    column.getName());
+                    column.getName(), false);
             for (int i = 0; i < columns.length; i++) {
                 if (expr.getColumnName().equals(columns[i].getName())) {
                     if (condition == null) {

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

@@ -23,6 +23,7 @@ import org.h2.message.DbException;
 import org.h2.result.ResultInterface;
 import org.h2.result.Row;
 import org.h2.result.RowImpl;
+import org.h2.table.Column;
 import org.h2.table.Table;
 import org.h2.table.TableFilter;
 import org.h2.util.Utils;
@@ -422,7 +423,7 @@ public class MergeUsing extends Prepared {
         targetMatchQuery = new Select(session, null);
         ArrayList<Expression> expressions = new ArrayList<>(1);
         expressions.add(new ExpressionColumn(session.getDatabase(), targetTable.getSchema().getName(),
-                targetTableFilter.getTableAlias(), "_ROWID_"));
+                targetTableFilter.getTableAlias(), Column.ROWID, true));
         targetMatchQuery.setExpressions(expressions);
         targetMatchQuery.addTableFilter(targetTableFilter, true);
         targetMatchQuery.addCondition(onCondition);

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

@@ -1049,7 +1049,7 @@ public class Select extends Query {
             }
             String name = filter.getDerivedColumnName(c);
             ExpressionColumn ec = new ExpressionColumn(
-                    session.getDatabase(), null, alias, name != null ? name : c.getName());
+                    session.getDatabase(), null, alias, name != null ? name : c.getName(), false);
             expressions.add(index++, ec);
         }
         return index;

h2/src/main/org/h2/engine/Constants.java

@@ -401,6 +401,16 @@ public class Constants {
      */
     public static final int SALT_LEN = 8;
 
+    /**
+     * The identity of INFORMATION_SCHEMA.
+     */
+    public static final int INFORMATION_SCHEMA_ID = -1;
+
+    /**
+     * The identity of PUBLIC schema.
+     */
+    public static final int MAIN_SCHEMA_ID = 0;
+
     /**
      * The name of the default schema.
      */

h2/src/main/org/h2/engine/Database.java

@@ -82,7 +82,7 @@ import org.h2.util.TempFileDeleter;
 import org.h2.util.Utils;
 import org.h2.value.CaseInsensitiveMap;
 import org.h2.value.CompareMode;
-import org.h2.value.NullableKeyConcurrentMap;
+import org.h2.value.CaseInsensitiveConcurrentMap;
 import org.h2.value.Value;
 import org.h2.value.ValueInt;
 
@@ -660,7 +660,8 @@ public class Database implements DataHandler {
         if (n == null || n.isEmpty()) {
             n = "unnamed";
         }
-        return dbSettings.databaseToUpper ? StringUtils.toUpperEnglish(n) : n;
+        return dbSettings.databaseToUpper ? StringUtils.toUpperEnglish(n)
+                : dbSettings.databaseToLower ? StringUtils.toLowerEnglish(n) : n;
     }
 
     private synchronized void open(int traceLevelFile, int traceLevelSystemOut, ConnectionInfo ci) {
@@ -788,12 +789,14 @@ public class Database implements DataHandler {
             store.getTransactionStore().init();
         }
         systemUser = new User(this, 0, SYSTEM_USER_NAME, true);
-        mainSchema = new Schema(this, 0, Constants.SCHEMA_MAIN, systemUser, true);
-        infoSchema = new Schema(this, -1, "INFORMATION_SCHEMA", systemUser, true);
+        mainSchema = new Schema(this, Constants.MAIN_SCHEMA_ID, sysIdentifier(Constants.SCHEMA_MAIN), systemUser,
+                true);
+        infoSchema = new Schema(this, Constants.INFORMATION_SCHEMA_ID, sysIdentifier("INFORMATION_SCHEMA"), systemUser,
+                true);
         schemas.put(mainSchema.getName(), mainSchema);
         schemas.put(infoSchema.getName(), infoSchema);
-        publicRole = new Role(this, 0, Constants.PUBLIC_ROLE_NAME, true);
-        roles.put(Constants.PUBLIC_ROLE_NAME, publicRole);
+        publicRole = new Role(this, 0, sysIdentifier(Constants.PUBLIC_ROLE_NAME), true);
+        roles.put(publicRole.getName(), publicRole);
         systemUser.setAdmin(true);
         systemSession = new Session(this, systemUser, ++nextSessionId);
         lobSession = new Session(this, systemUser, ++nextSessionId);
@@ -1687,6 +1690,15 @@ public class Database implements DataHandler {
         return i;
     }
 
+    /**
+     * Returns main schema (usually PUBLIC).
+     *
+     * @return main schema (usually PUBLIC)
+     */
+    public Schema getMainSchema() {
+        return mainSchema;
+    }
+
     public ArrayList<UserAggregate> getAllAggregates() {
         return new ArrayList<>(aggregates.values());
     }
@@ -2760,8 +2772,8 @@ public class Database implements DataHandler {
                     continue;
                 }
                 // exclude the LOB_MAP that the Recover tool creates
-                if (table.getName().equals("LOB_BLOCKS") && table.getSchema()
-                        .getName().equals("INFORMATION_SCHEMA")) {
+                if (table.getSchema().getId() == Constants.INFORMATION_SCHEMA_ID
+                        && table.getName().equalsIgnoreCase("LOB_BLOCKS")) {
                     continue;
                 }
                 return table;
@@ -3041,9 +3053,7 @@ public class Database implements DataHandler {
      * @return the hash map
      */
     public <V> HashMap<String, V> newStringMap() {
-        return dbSettings.databaseToUpper ?
-                new HashMap<String, V>() :
-                new CaseInsensitiveMap<V>();
+        return dbSettings.caseInsensitiveIdentifiers ? new CaseInsensitiveMap<V>() : new HashMap<String, V>();
     }
 
     /**
@@ -3054,7 +3064,8 @@ public class Database implements DataHandler {
      * @return the hash map
      */
     public <V> ConcurrentHashMap<String, V> newConcurrentStringMap() {
-        return new NullableKeyConcurrentMap<>(!dbSettings.databaseToUpper);
+        return dbSettings.caseInsensitiveIdentifiers ? new CaseInsensitiveConcurrentMap<V>()
+                : new ConcurrentHashMap<String, V>();
     }
 
     /**
@@ -3066,7 +3077,33 @@ public class Database implements DataHandler {
      * @return true if they match
      */
     public boolean equalsIdentifiers(String a, String b) {
-        return a.equals(b) || (!dbSettings.databaseToUpper && a.equalsIgnoreCase(b));
+        return a.equals(b) || dbSettings.caseInsensitiveIdentifiers && a.equalsIgnoreCase(b);
+    }
+
+    /**
+     * Returns identifier in upper or lower case depending on database settings.
+     *
+     * @param upperName
+     *            identifier in the upper case
+     * @return identifier in upper or lower case
+     */
+    public String sysIdentifier(String upperName) {
+        assert isUpperSysIdentifier(upperName);
+        return dbSettings.databaseToLower ? StringUtils.toLowerEnglish(upperName) : upperName;
+    }
+
+    private static boolean isUpperSysIdentifier(String upperName) {
+        int l = upperName.length();
+        if (l == 0) {
+            return false;
+        }
+        for (int i = 0; i < l; i++) {
+            int ch = upperName.charAt(i);
+            if (ch < 'A' || ch > 'Z' && ch != '_') {
+                return false;
+            }
+        }
+        return true;
     }
 
     @Override

h2/src/main/org/h2/engine/DbSettings.java

@@ -6,6 +6,7 @@
 package org.h2.engine;
 
 import java.util.HashMap;
+import org.h2.api.ErrorCode;
 import org.h2.message.DbException;
 import org.h2.util.Utils;
 
@@ -55,15 +56,28 @@ public class DbSettings extends SettingsBase {
      */
     public final int analyzeSample = get("ANALYZE_SAMPLE", 10_000);
 
+    /**
+     * Database setting <code>DATABASE_TO_LOWER</code> (default: false).<br />
+     * Database short names are converted to lowercase for the DATABASE()
+     * function, and in the CATALOG column of all database meta data methods.
+     * Setting this to "true" is experimental.
+     */
+    public final boolean databaseToLower;
+
     /**
      * Database setting <code>DATABASE_TO_UPPER</code> (default: true).<br />
      * Database short names are converted to uppercase for the DATABASE()
      * function, and in the CATALOG column of all database meta data methods.
-     * Setting this to "false" is experimental. When set to false, all
-     * identifier names (table names, column names) are case sensitive (except
-     * aggregate, built-in functions, data types, and keywords).
      */
-    public final boolean databaseToUpper = get("DATABASE_TO_UPPER", true);
+    public final boolean databaseToUpper;
+
+    /**
+     * Database setting <code>CASE_INSENSITIVE_IDENTIFIERS</code> (default:
+     * false).<br />
+     * When set to true, all identifier names (table names, column names) are
+     * case insensitive. Setting this to "true" is experimental.
+     */
+    public final boolean caseInsensitiveIdentifiers = get("CASE_INSENSITIVE_IDENTIFIERS", false);
 
     /**
      * Database setting <code>DB_CLOSE_ON_EXIT</code> (default: true).<br />
@@ -284,12 +298,6 @@ public class DbSettings extends SettingsBase {
      */
     public final boolean reuseSpace = get("REUSE_SPACE", true);
 
-    /**
-     * Database setting <code>ROWID</code> (default: true).<br />
-     * If set, each table has a pseudo-column _ROWID_.
-     */
-    public final boolean rowId = get("ROWID", true);
-
     /**
      * Database setting <code>SHARE_LINKED_CONNECTIONS</code>
      * (default: true).<br />
@@ -337,6 +345,18 @@ public class DbSettings extends SettingsBase {
         if (s.get("NESTED_JOINS") != null || Utils.getProperty("h2.nestedJoins", null) != null) {
             throw DbException.getUnsupportedException("NESTED_JOINS setting is not available since 1.4.197");
         }
+        boolean lower = get("DATABASE_TO_LOWER", false);
+        boolean upperSet = containsKey("DATABASE_TO_UPPER");
+        boolean upper = get("DATABASE_TO_UPPER", true);
+        if (lower && upper) {
+            if (upperSet) {
+                throw DbException.get(ErrorCode.UNSUPPORTED_SETTING_COMBINATION,
+                        "DATABASE_TO_LOWER & DATABASE_TO_UPPER");
+            }
+            upper = false;
+        }
+        databaseToLower = lower;
+        databaseToUpper = upper;
     }
 
     /**

h2/src/main/org/h2/engine/FunctionAlias.java

@@ -205,8 +205,7 @@ public class FunctionAlias extends SchemaObjectBase {
     @Override
     public StringBuilder getSQL(StringBuilder builder) {
         // TODO can remove this method once FUNCTIONS_IN_SCHEMA is enabled
-        if (database.getSettings().functionsInSchema ||
-                !getSchema().getName().equals(Constants.SCHEMA_MAIN)) {
+        if (database.getSettings().functionsInSchema || getSchema().getId() != Constants.MAIN_SCHEMA_ID) {
             return super.getSQL(builder);
         }
         return Parser.quoteIdentifier(builder, getName());

h2/src/main/org/h2/engine/Session.java

@@ -168,7 +168,6 @@ public class Session extends SessionWithState implements TransactionStore.Rollba
      */
     private BitSet idsToRelease;
 
-
     public Session(Database database, User user, int id) {
         this.database = database;
         this.queryTimeout = database.getSettings().maxQueryTimeout;
@@ -176,7 +175,10 @@ public class Session extends SessionWithState implements TransactionStore.Rollba
         this.user = user;
         this.id = id;
         this.lockTimeout = database.getLockTimeout();
-        this.currentSchemaName = Constants.SCHEMA_MAIN;
+        // PageStore creates a system session before initialization of the main schema
+        Schema mainSchema = database.getMainSchema();
+        this.currentSchemaName = mainSchema != null ? mainSchema.getName()
+                : database.sysIdentifier(Constants.SCHEMA_MAIN);
         this.columnNamerConfiguration = ColumnNamerConfiguration.getDefault();
     }
 

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

@@ -36,6 +36,7 @@ public class ExpressionColumn extends Expression {
     private final String schemaName;
     private final String tableAlias;
     private final String columnName;
+    private final boolean rowId;
     private ColumnResolver columnResolver;
     private int queryLevel;
     private Column column;
@@ -47,14 +48,16 @@ public class ExpressionColumn extends Expression {
         this.schemaName = null;
         this.tableAlias = null;
         this.columnName = null;
+        this.rowId = column.isRowId();
     }
 
     public ExpressionColumn(Database database, String schemaName,
-            String tableAlias, String columnName) {
+            String tableAlias, String columnName, boolean rowId) {
         this.database = database;
         this.schemaName = schemaName;
         this.tableAlias = tableAlias;
         this.columnName = columnName;
+        this.rowId = rowId;
     }
 
     @Override
@@ -71,6 +74,8 @@ public class ExpressionColumn extends Expression {
             } else {
                 column.getSQL(builder);
             }
+        } else if (rowId) {
+            builder.append(columnName);
         } else {
             Parser.quoteIdentifier(builder, columnName);
         }
@@ -91,6 +96,13 @@ public class ExpressionColumn extends Expression {
                 schemaName, resolver.getSchemaName())) {
             return;
         }
+        if (rowId) {
+            Column col = resolver.getRowIdColumn();
+            if (col != null) {
+                mapColumn(resolver, col, level);
+            }
+            return;
+        }
         for (Column col : resolver.getColumns()) {
             String n = resolver.getDerivedColumnName(col);
             boolean derived;
@@ -108,13 +120,6 @@ public class ExpressionColumn extends Expression {
                 return;
             }
         }
-        if (database.equalsIdentifiers(Column.ROWID, columnName)) {
-            Column col = resolver.getRowIdColumn();
-            if (col != null) {
-                mapColumn(resolver, col, level);
-                return;
-            }
-        }
         Column[] columns = resolver.getSystemColumns();
         for (int i = 0; columns != null && i < columns.length; i++) {
             Column col = columns[i];

h2/src/main/org/h2/expression/function/JavaFunction.java

@@ -84,7 +84,7 @@ public class JavaFunction extends Expression implements FunctionCall {
     public StringBuilder getSQL(StringBuilder builder) {
         // TODO always append the schema once FUNCTIONS_IN_SCHEMA is enabled
         if (functionAlias.getDatabase().getSettings().functionsInSchema ||
-                !functionAlias.getSchema().getName().equals(Constants.SCHEMA_MAIN)) {
+                functionAlias.getSchema().getId() != Constants.MAIN_SCHEMA_ID) {
             Parser.quoteIdentifier(builder, functionAlias.getSchema().getName()).append('.');
         }
         Parser.quoteIdentifier(builder, functionAlias.getName()).append('(');

h2/src/main/org/h2/jdbc/JdbcDatabaseMetaData.java

@@ -1551,7 +1551,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
      * EXISTS, FALSE, FETCH, FOR, FOREIGN, FROM, FULL, GROUP, HAVING,
      * IF, INNER, INTERSECT, INTERSECTS, INTERVAL, IS, JOIN, LIKE,
      * LIMIT, LOCALTIME, LOCALTIMESTAMP, MINUS, NATURAL, NOT, NULL,
-     * OFFSET, ON, ORDER, PRIMARY, QUALIFY, ROW, ROWNUM, SELECT,
+     * OFFSET, ON, ORDER, PRIMARY, QUALIFY, ROW, _ROWID_, ROWNUM, SELECT,
      * SYSDATE, SYSTIME, SYSTIMESTAMP, TABLE, TODAY, TOP, TRUE, UNION,
      * UNIQUE, VALUES, WHERE, WINDOW, WITH
      * </pre>
@@ -1561,7 +1561,7 @@ public class JdbcDatabaseMetaData extends TraceObject implements
     @Override
     public String getSQLKeywords() {
         debugCodeCall("getSQLKeywords");
-        return "IF,INTERSECTS,LIMIT,MINUS,OFFSET,QUALIFY,ROWNUM,SYSDATE,SYSTIME,SYSTIMESTAMP,TODAY,TOP";
+        return "IF,INTERSECTS,LIMIT,MINUS,OFFSET,QUALIFY,_ROWID_,ROWNUM,SYSDATE,SYSTIME,SYSTIMESTAMP,TODAY,TOP";
     }
 
     /**

h2/src/main/org/h2/mvstore/MVMap.java

@@ -1640,7 +1640,7 @@ public class MVMap<K, V> extends AbstractMap<K, V>
      * Add, replace or remove a key-value pair.
      *
      * @param key the key (may not be null)
-     * @param value new value, it may be null when removal is indended
+     * @param value new value, it may be null when removal is intended
      * @param decisionMaker command object to make choices during transaction.
      * @return previous value, if mapping for that key existed, or null otherwise
      */

h2/src/main/org/h2/mvstore/db/MVTable.java

@@ -876,6 +876,7 @@ public class MVTable extends TableBase {
         if (rowIdColumn == null) {
             rowIdColumn = new Column(Column.ROWID, Value.LONG);
             rowIdColumn.setTable(this, SearchRow.ROWID_INDEX);
+            rowIdColumn.setRowId(true);
         }
         return rowIdColumn;
     }

h2/src/main/org/h2/schema/Schema.java

@@ -343,7 +343,6 @@ public class Schema extends DbObjectBase {
             if (synonym != null) {
                 return synonym.getSynonymFor();
             }
-            return null;
         }
         return table;
     }

h2/src/main/org/h2/table/Column.java

@@ -84,6 +84,7 @@ public class Column {
     private String comment;
     private boolean primaryKey;
     private boolean visible = true;
+    private boolean rowId;
     private Domain domain;
 
     /**
@@ -288,11 +289,11 @@ public class Column {
     }
 
     public String getSQL() {
-        return Parser.quoteIdentifier(name);
+        return rowId ? name : Parser.quoteIdentifier(name);
     }
 
     public StringBuilder getSQL(StringBuilder builder) {
-        return Parser.quoteIdentifier(builder, name);
+        return rowId ? builder.append(name) : Parser.quoteIdentifier(builder, name);
     }
 
     public String getName() {
@@ -323,6 +324,24 @@ public class Column {
         this.domain = domain;
     }
 
+    /**
+     * Returns whether this column is a row identity column.
+     *
+     * @return true for _ROWID_ column, false otherwise
+     */
+    public boolean isRowId() {
+        return rowId;
+    }
+
+    /**
+     * Set row identity flag.
+     *
+     * @param rowId true _ROWID_ column, false otherwise
+     */
+    public void setRowId(boolean rowId) {
+        this.rowId = rowId;
+    }
+
     /**
      * Validate the value, convert it if required, and update the sequence value
      * if required. If the value is null, the default value (NULL if no default

h2/src/main/org/h2/table/RegularTable.java

@@ -729,6 +729,7 @@ public class RegularTable extends TableBase {
         if (rowIdColumn == null) {
             rowIdColumn = new Column(Column.ROWID, Value.LONG);
             rowIdColumn.setTable(this, -1);
+            rowIdColumn.setRowId(true);
         }
         return rowIdColumn;
     }

h2/src/main/org/h2/table/TableFilter.java

@@ -1053,11 +1053,8 @@ public class TableFilter implements ColumnResolver {
 
     @Override
     public Column getRowIdColumn() {
-        if (session.getDatabase().getSettings().rowId) {
         return table.getRowIdColumn();
     }
-        return null;
-    }
 
     @Override
     public Value getValue(Column column) {

h2/src/main/org/h2/table/TableView.java

@@ -16,7 +16,6 @@ import org.h2.command.Prepared;
 import org.h2.command.ddl.CreateTableData;
 import org.h2.command.dml.AllColumnsForPlan;
 import org.h2.command.dml.Query;
-import org.h2.engine.Constants;
 import org.h2.engine.Database;
 import org.h2.engine.DbObject;
 import org.h2.engine.Session;
@@ -547,7 +546,7 @@ public class TableView extends Table {
      */
     public static TableView createTempView(Session session, User owner,
             String name, Query query, Query topQuery) {
-        Schema mainSchema = session.getDatabase().getSchema(Constants.SCHEMA_MAIN);
+        Schema mainSchema = session.getDatabase().getMainSchema();
         String querySQL = query.getPlanSQL();
         TableView v = new TableView(mainSchema, 0, name,
                 querySQL, query.getParameters(), null /* column templates */, session,

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

@@ -227,10 +227,15 @@ public class ParserUtil {
      */
     public static final int ROW = QUALIFY + 1;
 
+    /**
+     * The token "_ROWID_".
+     */
+    public static final int _ROWID_ = ROW + 1;
+
     /**
      * The token "ROWNUM".
      */
-    public static final int ROWNUM = ROW + 1;
+    public static final int ROWNUM = _ROWID_ + 1;
 
     /**
      * The token "SELECT".
@@ -352,10 +357,7 @@ public class ParserUtil {
          */
         char c = s.charAt(start);
         if (ignoreCase) {
-            /*
-             * Convert a-z to A-Z. This method is safe, because only A-Z
-             * characters are considered below.
-             */
+            // Convert a-z to A-Z and 0x7f to _ (need special handling).
             c &= 0xffdf;
         }
         switch (c) {
@@ -537,6 +539,12 @@ public class ParserUtil {
                 return WITH;
             }
             return IDENTIFIER;
+        case '_':
+            // Cannot use eq() because 0x7f can be converted to '_' (0x5f)
+            if (end - start == 7 && "_ROWID_".regionMatches(ignoreCase, 0, s, start, 7)) {
+                return _ROWID_;
+            }
+            //$FALL-THROUGH$
         default:
             return IDENTIFIER;
         }

h2/src/main/org/h2/value/NullableKeyConcurrentMap.java → h2/src/main/org/h2/value/CaseInsensitiveConcurrentMap.java

@@ -10,53 +10,32 @@ import java.util.concurrent.ConcurrentHashMap;
 import org.h2.util.StringUtils;
 
 /**
- * A concurrent hash map with string keys that allows null keys.
+ * A concurrent hash map with case-insensitive string keys.
  *
  * @param <V> the value type
  */
-public class NullableKeyConcurrentMap<V> extends ConcurrentHashMap<String, V> {
+public class CaseInsensitiveConcurrentMap<V> extends ConcurrentHashMap<String, V> {
 
     private static final long serialVersionUID = 1L;
-    private static final String NULL = new String();
-
-    private final boolean toUpper;
-
-    /**
-     * Create new instance of map.
-     *
-     * @param toUpper
-     *                    whether keys should be converted to upper case
-     */
-    public NullableKeyConcurrentMap(boolean toUpper) {
-        this.toUpper = toUpper;
-    }
 
     @Override
     public V get(Object key) {
-        return super.get(toUpper(key));
+        return super.get(StringUtils.toUpperEnglish((String) key));
     }
 
     @Override
     public V put(String key, V value) {
-        return super.put(toUpper(key), value);
+        return super.put(StringUtils.toUpperEnglish(key), value);
     }
 
     @Override
     public boolean containsKey(Object key) {
-        return super.containsKey(toUpper(key));
+        return super.containsKey(StringUtils.toUpperEnglish((String) key));
     }
 
     @Override
     public V remove(Object key) {
-        return super.remove(toUpper(key));
-    }
-
-    private String toUpper(Object key) {
-        if (key == null) {
-            return NULL;
-        }
-        String s = key.toString();
-        return toUpper ? StringUtils.toUpperEnglish(s) : s;
+        return super.remove(StringUtils.toUpperEnglish((String) key));
     }
 
 }

h2/src/main/org/h2/value/CaseInsensitiveMap.java

@@ -19,26 +19,22 @@ public class CaseInsensitiveMap<V> extends HashMap<String, V> {
 
     @Override
     public V get(Object key) {
-        return super.get(toUpper(key));
+        return super.get(StringUtils.toUpperEnglish((String) key));
     }
 
     @Override
     public V put(String key, V value) {
-        return super.put(toUpper(key), value);
+        return super.put(StringUtils.toUpperEnglish(key), value);
     }
 
     @Override
     public boolean containsKey(Object key) {
-        return super.containsKey(toUpper(key));
+        return super.containsKey(StringUtils.toUpperEnglish((String) key));
     }
 
     @Override
     public V remove(Object key) {
-        return super.remove(toUpper(key));
-    }
-
-    private static String toUpper(Object key) {
-        return key == null ? null : StringUtils.toUpperEnglish(key.toString());
+        return super.remove(StringUtils.toUpperEnglish((String) key));
     }
 
 }

h2/src/test/org/h2/test/db/TestCompatibility.java

@@ -14,6 +14,7 @@ import java.sql.ResultSet;
 import java.sql.ResultSetMetaData;
 import java.sql.SQLException;
 import java.sql.Statement;
+import java.util.Locale;
 import org.h2.api.ErrorCode;
 import org.h2.test.TestBase;
 import org.h2.test.TestDb;
@@ -57,6 +58,7 @@ public class TestCompatibility extends TestDb {
         testUnknownSet();
 
         conn.close();
+        testIdentifiers();
         deleteDb("compatibility");
 
         testUnknownURL();
@@ -71,7 +73,7 @@ public class TestCompatibility extends TestDb {
     }
 
     private void testCaseSensitiveIdentifiers() throws SQLException {
-        Connection c = getConnection("compatibility;DATABASE_TO_UPPER=FALSE");
+        Connection c = getConnection("compatibility;DATABASE_TO_UPPER=FALSE;CASE_INSENSITIVE_IDENTIFIERS=TRUE");
         Statement stat = c.createStatement();
         stat.execute("create table test(id int primary key, name varchar) " +
                 "as select 1, 'hello'");
@@ -682,6 +684,62 @@ public class TestCompatibility extends TestDb {
         assertThrows(ErrorCode.UNKNOWN_MODE_1, stat).execute("SET MODE Unknown");
     }
 
+    private void testIdentifiers() throws SQLException {
+        deleteDb("compatibility");
+        testIdentifiers(false, false, false);
+        testIdentifiers(false, false, true);
+        testIdentifiers(true, false, false);
+        testIdentifiers(true, false, true);
+        testIdentifiers(false, true, false);
+        testIdentifiers(false, true, true);
+    }
+
+    private void testIdentifiers(boolean upper, boolean lower, boolean caseInsensitiveIdentifiers) throws SQLException
+    {
+        try (Connection conn = getConnection("compatibility;DATABASE_TO_UPPER=" + upper + ";DATABASE_TO_LOWER=" + lower
+                + ";CASE_INSENSITIVE_IDENTIFIERS=" + caseInsensitiveIdentifiers)) {
+            Statement stat = conn.createStatement();
+            stat.execute("CREATE TABLE Test(Id INT) AS VALUES 2");
+            String schema = "PUBLIC", table = "Test", column = "Id";
+            if (upper) {
+                table = table.toUpperCase(Locale.ROOT);
+                column = column.toUpperCase(Locale.ROOT);
+            } else if (lower) {
+                schema = schema.toLowerCase(Locale.ROOT);
+                table = table.toLowerCase(Locale.ROOT);
+                column = column.toLowerCase(Locale.ROOT);
+            }
+            try (ResultSet rs = stat.executeQuery("SELECT TABLE_SCHEMA, TABLE_NAME, COLUMN_NAME"
+                    + " FROM INFORMATION_SCHEMA.COLUMNS WHERE TABLE_NAME ILIKE 'Test'")) {
+                assertTrue(rs.next());
+                assertEquals(schema, rs.getString(1));
+                assertEquals(table, rs.getString(2));
+                assertEquals(column, rs.getString(3));
+            }
+            testIdentifiers(stat, "Test", "Id", true);
+            boolean ok = upper || lower || caseInsensitiveIdentifiers;
+            testIdentifiers(stat, "TEST", "ID", ok);
+            testIdentifiers(stat, "test", "id", ok);
+            testIdentifiers(stat, '"' + table + '"', '"' + column + '"', true);
+            testIdentifiers(stat, "\"TeSt\"", "\"iD\"", caseInsensitiveIdentifiers);
+        } finally {
+            deleteDb("compatibility");
+        }
+    }
+
+    private void testIdentifiers(Statement stat, String table, String column, boolean ok) throws SQLException {
+        String query = "SELECT _ROWID_, " + column + " FROM " + table;
+        if (ok) {
+            try (ResultSet rs = stat.executeQuery(query)) {
+                assertTrue(rs.next());
+                assertEquals(1L, rs.getLong(1));
+                assertEquals(2, rs.getInt(2));
+            }
+        } else {
+            assertThrows(ErrorCode.TABLE_OR_VIEW_NOT_FOUND_1, stat).executeQuery(query);
+        }
+    }
+
     private void testUnknownURL() throws SQLException {
         try {
             getConnection("compatibility;MODE=Unknown").close();

h2/src/test/org/h2/test/jdbc/TestMetaData.java

@@ -463,7 +463,7 @@ public class TestMetaData extends TestDb {
 
         assertEquals("schema", meta.getSchemaTerm());
         assertEquals("\\", meta.getSearchStringEscape());
-        assertEquals("IF,INTERSECTS,LIMIT,MINUS,OFFSET,QUALIFY,ROWNUM,SYSDATE,SYSTIME,SYSTIMESTAMP,TODAY,TOP",
+        assertEquals("IF,INTERSECTS,LIMIT,MINUS,OFFSET,QUALIFY,_ROWID_,ROWNUM,SYSDATE,SYSTIME,SYSTIMESTAMP,TODAY,TOP",
                 meta.getSQLKeywords());
 
         assertTrue(meta.getURL().startsWith("jdbc:h2:"));

h2/src/test/org/h2/test/scripts/dml/insert.sql

@@ -28,3 +28,19 @@ TABLE TEST;
 
 DROP TABLE TEST;
 > ok
+
+CREATE TABLE TEST(ID INT);
+> ok
+
+-- TODO Do we need _ROWID_ support here?
+INSERT INTO TEST(_ROWID_, ID) VALUES (2, 3);
+> update count: 1
+
+SELECT _ROWID_, ID FROM TEST;
+> _ROWID_ ID
+> ------- --
+> 2       3
+> rows: 1
+
+DROP TABLE TEST;
+> ok

h2/src/test/org/h2/test/scripts/dml/select.sql

@@ -640,3 +640,17 @@ SELECT * FROM
 > ----- -
 > 36    2
 > rows: 1
+
+CREATE TABLE TEST("_ROWID_" INT) AS VALUES 2;
+> ok
+
+SELECT _ROWID_ S1, TEST._ROWID_ S2, PUBLIC.TEST._ROWID_ S3, SCRIPT.PUBLIC.TEST._ROWID_ S4,
+    "_ROWID_" U1, TEST."_ROWID_" U2, PUBLIC.TEST."_ROWID_" U3, SCRIPT.PUBLIC.TEST."_ROWID_" U4
+    FROM TEST;
+> S1 S2 S3 S4 U1 U2 U3 U4
+> -- -- -- -- -- -- -- --
+> 1  1  1  1  2  2  2  2
+> rows: 1
+
+DROP TABLE TEST;
+> ok

h2/src/test/org/h2/test/scripts/dml/update.sql

@@ -38,3 +38,28 @@ SELECT B FROM TEST;
 
 DROP TABLE TEST;
 > ok
+
+CREATE TABLE TEST(ID INT) AS VALUES 100;
+> ok
+
+SELECT _ROWID_ FROM TEST;
+>> 1
+
+-- _ROWID_ modifications are ignored
+UPDATE TEST SET _ROWID_ = 2 WHERE ID = 100;
+> update count: 1
+
+UPDATE TEST SET TEST._ROWID_ = 3 WHERE ID = 100;
+> update count: 1
+
+UPDATE TEST SET PUBLIC.TEST._ROWID_ = 4 WHERE ID = 100;
+> update count: 1
+
+UPDATE TEST SET SCRIPT.PUBLIC.TEST._ROWID_ = 5 WHERE ID = 100;
+> update count: 1
+
+SELECT _ROWID_ FROM TEST;
+>> 1
+
+DROP TABLE TEST;
+> ok

h2/src/test/org/h2/test/unit/TestKeywords.java

@@ -79,12 +79,10 @@ public class TestKeywords extends TestBase {
         try (Connection conn = DriverManager.getConnection("jdbc:h2:mem:keywords")) {
             Statement stat = conn.createStatement();
             for (String s : set) {
-                // _ROWID_ is a special virtual column
-                String column = s.equals("_ROWID_") ? "C" : s;
                 try {
-                    stat.execute("CREATE TABLE " + s + '(' + column + " INT)");
-                    stat.execute("INSERT INTO " + s + '(' + column + ") VALUES (10)");
-                    try (ResultSet rs = stat.executeQuery("SELECT " + column + " FROM " + s)) {
+                    stat.execute("CREATE TABLE " + s + '(' + s + " INT)");
+                    stat.execute("INSERT INTO " + s + '(' + s + ") VALUES (10)");
+                    try (ResultSet rs = stat.executeQuery("SELECT " + s + " FROM " + s)) {
                         assertTrue(rs.next());
                         assertEquals(10, rs.getInt(1));
                         assertFalse(rs.next());

h2/src/test/org/h2/test/unit/TestPgServer.java

@@ -73,7 +73,7 @@ public class TestPgServer extends TestDb {
         }
         deleteDb("pgserver");
         Connection conn = getConnection(
-                "mem:pgserver;DATABASE_TO_UPPER=false", "sa", "sa");
+                "mem:pgserver;DATABASE_TO_LOWER=true", "sa", "sa");
         Statement stat = conn.createStatement();
         stat.execute("create table test(id int, name varchar(255))");
         Server server = createPgServer("-baseDir", getBaseDir(),