diff --git a/source/const.inc b/source/const.inc
index a5606923..1fbfd040 100644
--- a/source/const.inc
+++ b/source/const.inc
@@ -165,39 +165,6 @@ const
   CLIENT_SSL_VERIFY_SERVER_CERT = 67108864;
   CLIENT_REMEMBER_OPTIONS = 134217728;
 
-  // Enum Field Types
-  FIELD_TYPE_DECIMAL = 0;
-  FIELD_TYPE_TINY = 1;
-  FIELD_TYPE_SHORT = 2;
-  FIELD_TYPE_LONG = 3;
-  FIELD_TYPE_FLOAT = 4;
-  FIELD_TYPE_DOUBLE = 5;
-  FIELD_TYPE_NULL = 6;
-  FIELD_TYPE_TIMESTAMP = 7;
-  FIELD_TYPE_LONGLONG = 8;
-  FIELD_TYPE_INT24 = 9;
-  FIELD_TYPE_DATE = 10;
-  FIELD_TYPE_TIME = 11;
-  FIELD_TYPE_DATETIME = 12;
-  FIELD_TYPE_YEAR = 13;
-  FIELD_TYPE_NEWDATE = 14;
-  FIELD_TYPE_VARCHAR = 15;
-  FIELD_TYPE_BIT = 16;
-  FIELD_TYPE_TIMESTAMP2 = 17;
-  FIELD_TYPE_DATETIME2 = 18;
-  FIELD_TYPE_TIME2 = 19;
-  FIELD_TYPE_JSON = 245;
-  FIELD_TYPE_NEWDECIMAL = 246;
-  FIELD_TYPE_ENUM = 247;
-  FIELD_TYPE_SET = 248;
-  FIELD_TYPE_TINY_BLOB = 249;
-  FIELD_TYPE_MEDIUM_BLOB = 250;
-  FIELD_TYPE_LONG_BLOB = 251;
-  FIELD_TYPE_BLOB = 252;
-  FIELD_TYPE_VAR_STRING = 253;
-  FIELD_TYPE_STRING = 254;
-  FIELD_TYPE_GEOMETRY = 255;
-
   COLLATION_BINARY = 63;
   // Equivalent to COLLATION_BINARY, this is what a new driver returns when connected to a pre-4.1 server.
   COLLATION_NONE =  0;
diff --git a/source/dbconnection.pas b/source/dbconnection.pas
index 45dced17..2fc73241 100644
--- a/source/dbconnection.pas
+++ b/source/dbconnection.pas
@@ -5364,7 +5364,7 @@ begin
           end else if (Field.flags and SET_FLAG) = SET_FLAG then begin
             if FConnection.Datatypes[j].Index = dtSet then
               FColumnTypes[i] := FConnection.Datatypes[j];
-          end else if Field._type = FConnection.Datatypes[j].NativeType then begin
+          end else if Field._type = Cardinal(FConnection.Datatypes[j].NativeType) then begin
             // Text and Blob types share the same constants (see FIELD_TYPEs)
             // Some function results return binary collation up to the latest versions. Work around
             // that by checking if this field is a real table field
diff --git a/source/mysql_structures.pas b/source/mysql_structures.pas
index 9c4b15ba..177bf2bb 100644
--- a/source/mysql_structures.pas
+++ b/source/mysql_structures.pas
@@ -195,10 +195,15 @@ type
   // MySQL data type categorization
   TDBDatatypeCategoryIndex = (dtcInteger, dtcReal, dtcText, dtcBinary, dtcTemporal, dtcSpatial, dtcOther);
 
+  // MySQL native column type constants. See include/mysql.h.pp in the server code
+  TMySQLType = (mytDecimal, mytTiny, mytShort, mytLong, mytFloat, mytDouble, mytNull, mytTimestamp,
+    mytLonglong, mytInt24, mytDate, mytTime, mytDatetime, mytYear, mytNewdate, mytVarchar,
+    mytBit, mytTimestamp2, mytDatetime2, mytTime2, mytJson=245, mytNewdecimal, mytEnum, mytSet, mytTinyblob,
+    mytMediumblob, mytLongblob, mytBlob, mytVarstring, mytString, mytGeometry);
   // MySQL data type structure
   TDBDatatype = record
     Index:           TDBDatatypeIndex;
-    NativeType:      Cardinal; // See field types
+    NativeType:      TMySQLType; // See above
     NativeTypes:     String; // Same as above, but for multiple postgresql oid's
     Name:            String;
     Names:           String;
@@ -280,7 +285,7 @@ var
   (
     (
       Index:           dtTinyint;
-      NativeType:      FIELD_TYPE_TINY;
+      NativeType:      mytTiny;
       Name:            'TINYINT';
       Description:     'TINYINT[(M)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A very small integer. The signed range is -128 to 127. ' +
@@ -294,7 +299,7 @@ var
     ),
     (
       Index:           dtSmallint;
-      NativeType:      FIELD_TYPE_SHORT;
+      NativeType:      mytShort;
       Name:            'SMALLINT';
       Description:     'SMALLINT[(M)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A small integer. The signed range is -32768 to 32767. ' +
@@ -308,7 +313,7 @@ var
     ),
     (
       Index:           dtMediumint;
-      NativeType:      FIELD_TYPE_INT24;
+      NativeType:      mytInt24;
       Name:            'MEDIUMINT';
       Description:     'MEDIUMINT[(M)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A medium-sized integer. The signed range is -8388608 to 8388607. ' +
@@ -322,7 +327,7 @@ var
     ),
     (
       Index:           dtInt;
-      NativeType:      FIELD_TYPE_LONG;
+      NativeType:      mytLong;
       Name:            'INT';
       Description:     'INT[(M)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A normal-size integer. The signed range is -2147483648 to 2147483647. ' +
@@ -336,7 +341,7 @@ var
     ),
     (
       Index:           dtBigint;
-      NativeType:      FIELD_TYPE_LONGLONG;
+      NativeType:      mytLonglong;
       Name:            'BIGINT';
       Description:     'BIGINT[(M)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A large integer. The signed range is -9223372036854775808 to ' +
@@ -350,7 +355,7 @@ var
     ),
     (
       Index:           dtFloat;
-      NativeType:      FIELD_TYPE_FLOAT;
+      NativeType:      mytFloat;
       Name:            'FLOAT';
       Description:     'FLOAT[(M,D)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A small (single-precision) floating-point number. Allowable values are '+
@@ -367,7 +372,7 @@ var
     ),
     (
       Index:           dtDouble;
-      NativeType:      FIELD_TYPE_DOUBLE;
+      NativeType:      mytDouble;
       Name:            'DOUBLE';
       Description:     'DOUBLE[(M,D)] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A normal-size (double-precision) floating-point number. Allowable ' +
@@ -384,7 +389,7 @@ var
     ),
     (
       Index:           dtDecimal;
-      NativeType:      FIELD_TYPE_NEWDECIMAL;
+      NativeType:      mytNewdecimal;
       Name:            'DECIMAL';
       Description:     'DECIMAL[(M[,D])] [UNSIGNED] [ZEROFILL]' + CRLF +
         'A packed "exact" fixed-point number. M is the total number of digits ' +
@@ -404,7 +409,7 @@ var
     ),
     (
       Index:           dtDate;
-      NativeType:      FIELD_TYPE_DATE;
+      NativeType:      mytDate;
       Name:            'DATE';
       Description:     'DATE' + CRLF +
         'A date. The supported range is ''1000-01-01'' to ''9999-12-31''. MySQL ' +
@@ -420,7 +425,7 @@ var
     ),
     (
       Index:           dtTime;
-      NativeType:      FIELD_TYPE_TIME;
+      NativeType:      mytTime;
       Name:            'TIME';
       Description:     'TIME' + CRLF +
         'A time. The range is ''-838:59:59'' to ''838:59:59''. MySQL displays TIME ' +
@@ -436,7 +441,7 @@ var
     ),
     (
       Index:           dtYear;
-      NativeType:      FIELD_TYPE_YEAR;
+      NativeType:      mytYear;
       Name:            'YEAR';
       Description:     'YEAR[(2|4)]' + CRLF +
         'A year in two-digit or four-digit format. The default is four-digit ' +
@@ -455,7 +460,7 @@ var
     ),
     (
       Index:           dtDatetime;
-      NativeType:      FIELD_TYPE_DATETIME;
+      NativeType:      mytDatetime;
       Name:            'DATETIME';
       Description:     'DATETIME' + CRLF +
         'A date and time combination. The supported range is ''1000-01-01 ' +
@@ -472,7 +477,7 @@ var
     ),
     (
       Index:           dtTimestamp;
-      NativeType:      FIELD_TYPE_TIMESTAMP;
+      NativeType:      mytTimestamp;
       Name:            'TIMESTAMP';
       Description:     'TIMESTAMP' + CRLF +
         'A timestamp. The range is ''1970-01-01 00:00:01'' UTC to ''2038-01-09 ' +
@@ -491,7 +496,7 @@ var
     ),
     (
       Index:           dtChar;
-      NativeType:      FIELD_TYPE_STRING;
+      NativeType:      mytString;
       Name:            'CHAR';
       Description:     'CHAR[(M)]' + CRLF +
         'A fixed-length string that is always right-padded with spaces to the ' +
@@ -509,7 +514,7 @@ var
     ),
     (
       Index:           dtVarchar;
-      NativeType:      FIELD_TYPE_VAR_STRING;
+      NativeType:      mytVarstring;
       Name:            'VARCHAR';
       Description:     'VARCHAR(M)' + CRLF +
         'A variable-length string. M represents the maximum column length in ' +
@@ -531,7 +536,7 @@ var
     ),
     (
       Index:           dtTinytext;
-      NativeType:      FIELD_TYPE_TINY_BLOB;
+      NativeType:      mytTinyblob;
       Name:            'TINYTEXT';
       Description:     'TINYTEXT' + CRLF +
         'A TEXT column with a maximum length of 255 (28 - 1) characters. The ' +
@@ -547,7 +552,7 @@ var
     ),
     (
       Index:           dtText;
-      NativeType:      FIELD_TYPE_BLOB;
+      NativeType:      mytBlob;
       Name:            'TEXT';
       Description:     'TEXT[(M)]' + CRLF +
         'A TEXT column with a maximum length of 65,535 (216 - 1) characters. The ' +
@@ -566,7 +571,7 @@ var
     ),
     (
       Index:           dtMediumtext;
-      NativeType:      FIELD_TYPE_MEDIUM_BLOB;
+      NativeType:      mytMediumblob;
       Name:            'MEDIUMTEXT';
       Description:     'MEDIUMTEXT' + CRLF +
         'A TEXT column with a maximum length of 16,777,215 (224 - 1) characters. ' +
@@ -582,7 +587,7 @@ var
     ),
     (
       Index:           dtLongtext;
-      NativeType:      FIELD_TYPE_LONG_BLOB;
+      NativeType:      mytLongblob;
       Name:            'LONGTEXT';
       Description:     'LONGTEXT' + CRLF +
         'A TEXT column with a maximum length of 4,294,967,295 or 4GB (232 - 1) ' +
@@ -601,7 +606,7 @@ var
     ),
     (
       Index:           dtJson;
-      NativeType:      FIELD_TYPE_JSON;
+      NativeType:      mytJson;
       Name:            'JSON';
       Description:     'JSON' + CRLF +
         'Documents stored in JSON columns are converted to an internal format that '+
@@ -619,7 +624,7 @@ var
     ),
     (
       Index:           dtBinary;
-      NativeType:      FIELD_TYPE_STRING;
+      NativeType:      mytString;
       Name:            'BINARY';
       Description:     'BINARY(M)' + CRLF +
         'The BINARY type is similar to the CHAR type, but stores binary byte ' +
@@ -635,7 +640,7 @@ var
     ),
     (
       Index:           dtVarbinary;
-      NativeType:      FIELD_TYPE_VAR_STRING;
+      NativeType:      mytVarstring;
       Name:            'VARBINARY';
       Description:     'VARBINARY(M)' + CRLF +
         'The VARBINARY type is similar to the VARCHAR type, but stores binary ' +
@@ -651,7 +656,7 @@ var
     ),
     (
       Index:           dtTinyblob;
-      NativeType:      FIELD_TYPE_TINY_BLOB;
+      NativeType:      mytTinyblob;
       Name:           'TINYBLOB';
       Description:     'TINYBLOB' + CRLF +
         'A BLOB column with a maximum length of 255 (28 - 1) bytes. Each ' +
@@ -666,7 +671,7 @@ var
     ),
     (
       Index:           dtBlob;
-      NativeType:      FIELD_TYPE_BLOB;
+      NativeType:      mytBlob;
       Name:            'BLOB';
       Description:     'BLOB[(M)]' + CRLF +
         'A BLOB column with a maximum length of 65,535 (216 - 1) bytes. Each ' +
@@ -684,7 +689,7 @@ var
     ),
     (
       Index:           dtMediumblob;
-      NativeType:      FIELD_TYPE_MEDIUM_BLOB;
+      NativeType:      mytMediumblob;
       Name:            'MEDIUMBLOB';
       Description:     'MEDIUMBLOB' + CRLF +
         'A BLOB column with a maximum length of 16,777,215 (224 - 1) bytes. Each ' +
@@ -699,7 +704,7 @@ var
     ),
     (
       Index:           dtLongblob;
-      NativeType:      FIELD_TYPE_LONG_BLOB;
+      NativeType:      mytLongblob;
       Name:            'LONGBLOB';
       Description:     'LONGBLOB' + CRLF +
         'A BLOB column with a maximum length of 4,294,967,295 or 4GB (232 - 1) ' +
@@ -716,7 +721,7 @@ var
     ),
     (
       Index:           dtEnum;
-      NativeType:      FIELD_TYPE_ENUM;
+      NativeType:      mytEnum;
       Name:            'ENUM';
       Description:     'ENUM(''value1'',''value2'',...)' + CRLF +
         'An enumeration. A string object that can have only one value, chosen ' +
@@ -733,7 +738,7 @@ var
     ),
     (
       Index:           dtSet;
-      NativeType:      FIELD_TYPE_SET;
+      NativeType:      mytSet;
       Name:            'SET';
       Description:     'SET(''value1'',''value2'',...)' + CRLF +
         'A set. A string object that can have zero or more values, each of which ' +
@@ -750,7 +755,7 @@ var
     ),
     (
       Index:           dtBit;
-      NativeType:      FIELD_TYPE_BIT;
+      NativeType:      mytBit;
       Name:            'BIT';
       Description:     'BIT[(M)]' + CRLF +
         'A bit-field type. M indicates the number of bits per value, from 1 to ' +
@@ -764,7 +769,7 @@ var
     ),
     (
       Index:           dtPoint;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'POINT';
       Description:     'POINT(x,y)' + CRLF +
         'Constructs a WKB Point using its coordinates.';
@@ -777,7 +782,7 @@ var
     ),
     (
       Index:           dtLinestring;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'LINESTRING';
       Description:     'LINESTRING(pt1,pt2,...)' + CRLF +
         'Constructs a WKB LineString value from a number of WKB Point arguments. ' +
@@ -792,7 +797,7 @@ var
     ),
     (
       Index:           dtPolygon;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'POLYGON';
       Description:     'POLYGON(ls1,ls2,...)' + CRLF +
         'Constructs a WKB Polygon value from a number of WKB LineString ' +
@@ -807,7 +812,7 @@ var
     ),
     (
       Index:           dtGeometry;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'GEOMETRY';
       Description:     '';
       HasLength:       False;
@@ -819,7 +824,7 @@ var
     ),
     (
       Index:           dtMultipoint;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'MULTIPOINT';
       Description:     'MULTIPOINT(pt1,pt2,...)' + CRLF +
         'Constructs a WKB MultiPoint value using WKB Point arguments. If any ' +
@@ -833,7 +838,7 @@ var
     ),
     (
       Index:           dtMultilinestring;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'MULTILINESTRING';
       Description:     'MULTILINESTRING(ls1,ls2,...)' + CRLF +
         'Constructs a WKB MultiLineString value using WKB LineString arguments. ' +
@@ -847,7 +852,7 @@ var
     ),
     (
       Index:           dtMultipolygon;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'MULTIPOLYGON';
       Description:     'MULTIPOLYGON(poly1,poly2,...)' + CRLF +
         'Constructs a WKB MultiPolygon value from a set of WKB Polygon ' +
@@ -862,7 +867,7 @@ var
     ),
     (
       Index:           dtGeometrycollection;
-      NativeType:      FIELD_TYPE_GEOMETRY;
+      NativeType:      mytGeometry;
       Name:            'GEOMETRYCOLLECTION';
       Description:     'GEOMETRYCOLLECTION(g1,g2,...)' + CRLF +
         'Constructs a WKB GeometryCollection. If any argument is not a ' +