diff --git a/.github/FUNDING.yml b/.github/FUNDING.yml
index a17ed84..5191cbf 100644
--- a/.github/FUNDING.yml
+++ b/.github/FUNDING.yml
@@ -1 +1,2 @@
-open_collective: drawdb
\ No newline at end of file
+open_collective: drawdb
+buy_me_a_coffee: drawdb
\ No newline at end of file
diff --git a/src/components/EditorCanvas/Canvas.jsx b/src/components/EditorCanvas/Canvas.jsx
index d16b392..7587f12 100644
--- a/src/components/EditorCanvas/Canvas.jsx
+++ b/src/components/EditorCanvas/Canvas.jsx
@@ -23,6 +23,7 @@ import {
 } from "../../hooks";
 import { useTranslation } from "react-i18next";
 import { useEventListener } from "usehooks-ts";
+import { areFieldsCompatible } from "../../utils/utils";
 
 export default function Canvas() {
   const { t } = useTranslation();
@@ -34,7 +35,8 @@ export default function Canvas() {
     pointer,
   } = canvasContextValue;
 
-  const { tables, updateTable, relationships, addRelationship } = useDiagram();
+  const { tables, updateTable, relationships, addRelationship, database } =
+    useDiagram();
   const { areas, updateArea } = useAreas();
   const { notes, updateNote } = useNotes();
   const { layout } = useLayout();
@@ -399,8 +401,11 @@ export default function Canvas() {
     if (hoveredTable.tableId < 0) return;
     if (hoveredTable.field < 0) return;
     if (
-      tables[linkingLine.startTableId].fields[linkingLine.startFieldId].type !==
-      tables[hoveredTable.tableId].fields[hoveredTable.field].type
+      !areFieldsCompatible(
+        database,
+        tables[linkingLine.startTableId].fields[linkingLine.startFieldId],
+        tables[hoveredTable.tableId].fields[hoveredTable.field],
+      )
     ) {
       Toast.info(t("cannot_connect"));
       return;
diff --git a/src/components/EditorSidePanel/TablesTab/FieldDetails.jsx b/src/components/EditorSidePanel/TablesTab/FieldDetails.jsx
index f8d99c0..f844513 100644
--- a/src/components/EditorSidePanel/TablesTab/FieldDetails.jsx
+++ b/src/components/EditorSidePanel/TablesTab/FieldDetails.jsx
@@ -299,6 +299,44 @@ export default function FieldDetails({ data, tid, index }) {
           />
         </div>
       )}
+      {databases[database].hasUnsignedTypes &&
+        dbToTypes[database][data.type].signed && (
+          <div className="flex justify-between items-center my-3">
+            <div className="font-medium">{t("Unsigned")}</div>
+            <Checkbox
+              value="unsigned"
+              checked={data.unsigned}
+              onChange={(checkedValues) => {
+                setUndoStack((prev) => [
+                  ...prev,
+                  {
+                    action: Action.EDIT,
+                    element: ObjectType.TABLE,
+                    component: "field",
+                    tid: tid,
+                    fid: index,
+                    undo: {
+                      [checkedValues.target.value]:
+                        !checkedValues.target.checked,
+                    },
+                    redo: {
+                      [checkedValues.target.value]:
+                        checkedValues.target.checked,
+                    },
+                    message: t("edit_table", {
+                      tableName: tables[tid].name,
+                      extra: "[field]",
+                    }),
+                  },
+                ]);
+                setRedoStack([]);
+                updateField(tid, index, {
+                  unsigned: checkedValues.target.checked,
+                });
+              }}
+            />
+          </div>
+        )}
       <div className="font-semibold">{t("comment")}</div>
       <TextArea
         className="my-2"
diff --git a/src/data/databases.js b/src/data/databases.js
index 55c9187..58ffe76 100644
--- a/src/data/databases.js
+++ b/src/data/databases.js
@@ -13,6 +13,7 @@ export const databases = new Proxy(
       label: DB.MYSQL,
       image: mysqlImage,
       hasTypes: false,
+      hasUnsignedTypes: true,
     },
     [DB.POSTGRES]: {
       name: "PostgreSQL",
@@ -33,6 +34,7 @@ export const databases = new Proxy(
       label: DB.MARIADB,
       image: mariadbImage,
       hasTypes: false,
+      hasUnsignedTypes: true,
     },
     [DB.MSSQL]: {
       name: "MSSQL",
diff --git a/src/data/datatypes.js b/src/data/datatypes.js
index 77c0cd7..106af82 100644
--- a/src/data/datatypes.js
+++ b/src/data/datatypes.js
@@ -279,6 +279,7 @@ const mysqlTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    signed: true,
   },
   SMALLINT: {
     type: "SMALLINT",
@@ -289,6 +290,7 @@ const mysqlTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    signed: true,
   },
   MEDIUMINT: {
     type: "MEDIUMINT",
@@ -299,6 +301,7 @@ const mysqlTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    signed: true,
   },
   INTEGER: {
     type: "INTEGER",
@@ -309,6 +312,7 @@ const mysqlTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    signed: true,
   },
   BIGINT: {
     type: "BIGINT",
@@ -319,6 +323,7 @@ const mysqlTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    signed: true,
   },
   DECIMAL: {
     type: "DECIMAL",
@@ -698,6 +703,7 @@ const postgresTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    compatibleWith: ["SMALLSERIAL", "SERIAL", "BIGSERIAL", "INTEGER", "BIGINT"],
   },
   INTEGER: {
     type: "INTEGER",
@@ -708,6 +714,13 @@ const postgresTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    compatibleWith: [
+      "SMALLSERIAL",
+      "SERIAL",
+      "BIGSERIAL",
+      "SMALLINT",
+      "BIGINT",
+    ],
   },
   BIGINT: {
     type: "BIGINT",
@@ -718,6 +731,13 @@ const postgresTypesBase = {
     isSized: false,
     hasPrecision: false,
     canIncrement: true,
+    compatibleWith: [
+      "SMALLSERIAL",
+      "SERIAL",
+      "BIGSERIAL",
+      "INTEGER",
+      "SMALLINT",
+    ],
   },
   DECIMAL: {
     type: "DECIMAL",
@@ -763,6 +783,7 @@ const postgresTypesBase = {
     hasCheck: true,
     isSized: false,
     hasPrecision: false,
+    compatibleWith: ["INTEGER", "SERIAL", "BIGSERIAL", "SMALLINT", "BIGINT"],
   },
   SERIAL: {
     type: "SERIAL",
@@ -772,6 +793,13 @@ const postgresTypesBase = {
     hasCheck: true,
     isSized: false,
     hasPrecision: false,
+    compatibleWith: [
+      "INTEGER",
+      "SMALLSERIAL",
+      "BIGSERIAL",
+      "SMALLINT",
+      "BIGINT",
+    ],
   },
   BIGSERIAL: {
     type: "BIGSERIAL",
@@ -781,6 +809,7 @@ const postgresTypesBase = {
     hasCheck: true,
     isSized: false,
     hasPrecision: false,
+    compatibleWith: ["INTEGER", "SERIAL", "SMALLSERIAL", "SMALLINT", "BIGINT"],
   },
   MONEY: {
     type: "MONEY",
diff --git a/src/i18n/locales/en.js b/src/i18n/locales/en.js
index 1351788..944e44b 100644
--- a/src/i18n/locales/en.js
+++ b/src/i18n/locales/en.js
@@ -235,6 +235,7 @@ const en = {
     declare_array: "Declare array",
     empty_index_name: "Declared an index with no name in table '{{tableName}}'",
     didnt_find_diagram: "Oops! Didn't find the diagram.",
+    unsigned: "Unsigned",
   },
 };
 
diff --git a/src/utils/exportSQL/mariadb.js b/src/utils/exportSQL/mariadb.js
index 58d35f8..dc83b23 100644
--- a/src/utils/exportSQL/mariadb.js
+++ b/src/utils/exportSQL/mariadb.js
@@ -13,7 +13,7 @@ export function toMariaDB(diagram) {
             (field) =>
               `${exportFieldComment(field.comment)}\t\`${
                 field.name
-              }\` ${field.type}${field.notNull ? " NOT NULL" : ""}${
+              }\` ${field.type}${field.unsigned ? " UNSIGNED" : ""}${field.notNull ? " NOT NULL" : ""}${
                 field.increment ? " AUTO_INCREMENT" : ""
               }${field.unique ? " UNIQUE" : ""}${
                 field.default !== ""
diff --git a/src/utils/exportSQL/mysql.js b/src/utils/exportSQL/mysql.js
index 9f80401..e462ca6 100644
--- a/src/utils/exportSQL/mysql.js
+++ b/src/utils/exportSQL/mysql.js
@@ -13,7 +13,7 @@ export function toMySQL(diagram) {
             (field) =>
               `${exportFieldComment(field.comment)}\t\`${
                 field.name
-              }\` ${field.type}${field.size !== undefined && field.size !== "" ? "(" + field.size + ")" : ""}${
+              }\` ${field.type}${field.unsigned ? " UNSIGNED" : ""}${field.size !== undefined && field.size !== "" ? "(" + field.size + ")" : ""}${
                 field.notNull ? " NOT NULL" : ""
               }${
                 field.increment ? " AUTO_INCREMENT" : ""
diff --git a/src/utils/utils.js b/src/utils/utils.js
index a51919f..553c340 100644
--- a/src/utils/utils.js
+++ b/src/utils/utils.js
@@ -1,3 +1,5 @@
+import { dbToTypes } from "../data/datatypes";
+
 export function dataURItoBlob(dataUrl) {
   const byteString = atob(dataUrl.split(",")[1]);
   const mimeString = dataUrl.split(",")[0].split(":")[1].split(";")[0];
@@ -34,3 +36,13 @@ export function isKeyword(str) {
 export function isFunction(str) {
   return /\w+\([^)]*\)$/.test(str);
 }
+
+export function areFieldsCompatible(db, field1, field2) {
+  const same = field1.type === field2.type;
+  if (dbToTypes[db][field1.type].compatibleWith) {
+    return (
+      dbToTypes[db][field1.type].compatibleWith.includes(field2.type) || same
+    );
+  }
+  return same;
+}