Aliases for built-in data types can now be re-mapped.

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

@@ -3272,17 +3272,14 @@ public class Parser {
         } else {
             regular = true;
         }
-        DataType dataType = DataType.getTypeByName(original);
         long precision = -1;
         int displaySize = -1;
         int scale = -1;
         String comment = null;
         Column templateColumn = null;
-        if (dataType == null) {
-            UserDataType userDataType = database.findUserDataType(original);
-            if (userDataType == null) {
-                throw Message.getSQLException(ErrorCode.UNKNOWN_DATA_TYPE_1, currentToken);
-            }
+        DataType dataType;
+        UserDataType userDataType = database.findUserDataType(original);
+        if (userDataType != null) {
             templateColumn = userDataType.getColumn();
             dataType = DataType.getDataType(templateColumn.getType());
             comment = templateColumn.getComment();
@@ -3290,6 +3287,11 @@ public class Parser {
             precision = templateColumn.getPrecision();
             displaySize = templateColumn.getDisplaySize();
             scale = templateColumn.getScale();
+        } else {
+            dataType = DataType.getTypeByName(original);
+            if (dataType == null) {
+                throw Message.getSQLException(ErrorCode.UNKNOWN_DATA_TYPE_1, currentToken);
+            }
         }
         if (database.getIgnoreCase() && dataType.type == Value.STRING && !"VARCHAR_CASESENSITIVE".equals(original)) {
             original = "VARCHAR_IGNORECASE";

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

@@ -14,6 +14,7 @@ import org.h2.engine.Session;
 import org.h2.engine.UserDataType;
 import org.h2.message.Message;
 import org.h2.table.Column;
+import org.h2.value.DataType;
 
 /**
  * This class represents the statement
@@ -53,6 +54,10 @@ public class CreateUserDataType extends DefineCommand {
             }
             throw Message.getSQLException(ErrorCode.USER_DATA_TYPE_ALREADY_EXISTS_1, typeName);
         }
+        DataType builtIn = DataType.getTypeByName(typeName);
+        if (builtIn != null && !builtIn.hidden) {
+            throw Message.getSQLException(ErrorCode.USER_DATA_TYPE_ALREADY_EXISTS_1, typeName);
+        }
         int id = getObjectId(false, true);
         UserDataType type = new UserDataType(db, id, typeName);
         type.setColumn(column);

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

@@ -1615,9 +1615,11 @@ public class ErrorCode {
 
     /**
      * The error with code <code>90119</code> is thrown when
-     * trying to create a domain if an object with this name already exists.
+     * trying to create a domain if an object with this name already exists,
+     * or when trying to overload a built-in data type.
      * Example:
      * <pre>
+     * CREATE DOMAIN INTEGER AS VARCHAR;
      * CREATE DOMAIN EMAIL AS VARCHAR CHECK LOCATE('@', VALUE) > 0;
      * CREATE DOMAIN EMAIL AS VARCHAR CHECK LOCATE('@', VALUE) > 0;
      * </pre>

h2/src/test/org/h2/test/test-1.0.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+create domain integer as varchar;
+> exception
+
+create domain int as varchar;
+> ok
+
+create domain bit as int;
+> ok
+
+create table test(id bit);
+> ok
+
+script nodata nopasswords nosettings;
+> SCRIPT
+> --------------------------------------------------
+> -- 0 = SELECT COUNT(*) FROM PUBLIC.TEST;
+> CREATE CACHED TABLE PUBLIC.TEST(     ID VARCHAR );
+> CREATE DOMAIN BIT AS VARCHAR;
+> CREATE DOMAIN INT AS VARCHAR;
+> CREATE USER IF NOT EXISTS SA PASSWORD '' ADMIN;
+> rows: 5
+
+drop table test;
+> ok
+
+drop domain int;
+> ok
+
+drop domain bit;
+> ok
+
+create table test(id identity, parent bigint, foreign key(parent) references(id));
+> ok
+
+insert into test values(0, 0), (1, NULL), (2, 1), (3, 3), (4, 3);
+> update count: 5
+
+delete from test where id = 3;
+> exception
+
+delete from test where id = 0;
+> update count: 1
+
+delete from test where id = 1;
+> exception
+
+drop table test;
+> ok
+
 select iso_week('2006-12-31') w, iso_year('2007-12-31') y, iso_day_of_week('2007-12-31') w;
 > W  Y    W
 > -- ---- -

h2/src/test/org/h2/test/test-1.1.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+create domain integer as varchar;
+> exception
+
+create domain int as varchar;
+> ok
+
+create domain bit as int;
+> ok
+
+create table test(id bit);
+> ok
+
+script nodata nopasswords nosettings;
+> SCRIPT
+> --------------------------------------------------
+> -- 0 = SELECT COUNT(*) FROM PUBLIC.TEST;
+> CREATE CACHED TABLE PUBLIC.TEST(     ID VARCHAR );
+> CREATE DOMAIN BIT AS VARCHAR;
+> CREATE DOMAIN INT AS VARCHAR;
+> CREATE USER IF NOT EXISTS SA PASSWORD '' ADMIN;
+> rows: 5
+
+drop table test;
+> ok
+
+drop domain int;
+> ok
+
+drop domain bit;
+> ok
+
 create table test(id identity, parent bigint, foreign key(parent) references(id));
 > ok