diff --git a/packages/builder/src/components/backend/DataTable/modals/CreateEditColumn.svelte b/packages/builder/src/components/backend/DataTable/modals/CreateEditColumn.svelte
index aa21799ca2..83ed741b75 100644
--- a/packages/builder/src/components/backend/DataTable/modals/CreateEditColumn.svelte
+++ b/packages/builder/src/components/backend/DataTable/modals/CreateEditColumn.svelte
@@ -18,6 +18,11 @@
     FIELDS,
     AUTO_COLUMN_SUB_TYPES,
     RelationshipTypes,
+    ALLOWABLE_STRING_OPTIONS,
+    ALLOWABLE_NUMBER_OPTIONS,
+    ALLOWABLE_STRING_TYPES,
+    ALLOWABLE_NUMBER_TYPES,
+    SWITCHABLE_TYPES,
   } from "constants/backend"
   import { getAutoColumnInformation, buildAutoColumn } from "builderStore/utils"
   import { notifications } from "@budibase/bbui"
@@ -92,6 +97,9 @@
       opt.type === table.type &&
       table.sourceId === opt.sourceId
   )
+  $: typeEnabled =
+    !originalName ||
+    (originalName && SWITCHABLE_TYPES.indexOf(field.type) !== -1)
 
   async function saveColumn() {
     if (field.type === AUTO_TYPE) {
@@ -204,7 +212,14 @@
   }
 
   function getAllowedTypes() {
-    if (!external) {
+    if (originalName && ALLOWABLE_STRING_TYPES.indexOf(field.type) !== -1) {
+      return ALLOWABLE_STRING_OPTIONS
+    } else if (
+      originalName &&
+      ALLOWABLE_NUMBER_TYPES.indexOf(field.type) !== -1
+    ) {
+      return ALLOWABLE_NUMBER_OPTIONS
+    } else if (!external) {
       return [
         ...Object.values(fieldDefinitions),
         { name: "Auto Column", type: AUTO_TYPE },
@@ -259,7 +274,7 @@
   />
 
   <Select
-    disabled={originalName}
+    disabled={!typeEnabled}
     label="Type"
     bind:value={field.type}
     on:change={handleTypeChange}
diff --git a/packages/builder/src/constants/backend/index.js b/packages/builder/src/constants/backend/index.js
index 088db024a6..a0aaa22963 100644
--- a/packages/builder/src/constants/backend/index.js
+++ b/packages/builder/src/constants/backend/index.js
@@ -138,3 +138,19 @@ export const RelationshipTypes = {
   ONE_TO_MANY: "one-to-many",
   MANY_TO_ONE: "many-to-one",
 }
+
+export const ALLOWABLE_STRING_OPTIONS = [FIELDS.STRING, FIELDS.OPTIONS]
+
+export const ALLOWABLE_STRING_TYPES = ALLOWABLE_STRING_OPTIONS.map(
+  opt => opt.type
+)
+
+export const ALLOWABLE_NUMBER_OPTIONS = [FIELDS.NUMBER, FIELDS.BOOLEAN]
+
+export const ALLOWABLE_NUMBER_TYPES = ALLOWABLE_NUMBER_OPTIONS.map(
+  opt => opt.type
+)
+
+export const SWITCHABLE_TYPES = ALLOWABLE_NUMBER_TYPES.concat(
+  ALLOWABLE_STRING_TYPES
+)
diff --git a/packages/builder/src/stores/backend/tables.js b/packages/builder/src/stores/backend/tables.js
index baa9e38ab9..73a53445ee 100644
--- a/packages/builder/src/stores/backend/tables.js
+++ b/packages/builder/src/stores/backend/tables.js
@@ -2,6 +2,7 @@ import { writable, get } from "svelte/store"
 import { views, queries, datasources } from "./"
 import { cloneDeep } from "lodash/fp"
 import api from "builderStore/api"
+import { SWITCHABLE_TYPES } from "constants/backend"
 
 export function createTablesStore() {
   const store = writable({})
@@ -47,7 +48,11 @@ export function createTablesStore() {
       const field = updatedTable.schema[key]
       const oldField = oldTable?.schema[key]
       // if the type has changed then revert back to the old field
-      if (oldField != null && oldField?.type !== field.type) {
+      if (
+        oldField != null &&
+        oldField?.type !== field.type &&
+        SWITCHABLE_TYPES.indexOf(oldField?.type) === -1
+      ) {
         updatedTable.schema[key] = oldField
       }
       // field has been renamed
diff --git a/packages/server/src/api/controllers/table/external.js b/packages/server/src/api/controllers/table/external.js
index 48454fbce9..bd22fa25f4 100644
--- a/packages/server/src/api/controllers/table/external.js
+++ b/packages/server/src/api/controllers/table/external.js
@@ -8,6 +8,7 @@ const {
   generateForeignKey,
   generateJunctionTableName,
   foreignKeyStructure,
+  hasTypeChanged,
 } = require("./utils")
 const {
   DataSourceOperation,
@@ -172,6 +173,10 @@ exports.save = async function (ctx) {
     oldTable = await getTable(appId, ctx.request.body._id)
   }
 
+  if (hasTypeChanged(tableToSave, oldTable)) {
+    ctx.throw(400, "A column type has changed.")
+  }
+
   const db = new CouchDB(appId)
   const datasource = await db.get(datasourceId)
   const oldTables = cloneDeep(datasource.entities)
diff --git a/packages/server/src/api/controllers/table/internal.js b/packages/server/src/api/controllers/table/internal.js
index 898cd0593b..1556893e34 100644
--- a/packages/server/src/api/controllers/table/internal.js
+++ b/packages/server/src/api/controllers/table/internal.js
@@ -2,7 +2,7 @@ const CouchDB = require("../../../db")
 const linkRows = require("../../../db/linkedRows")
 const { getRowParams, generateTableID } = require("../../../db/utils")
 const { FieldTypes } = require("../../../constants")
-const { TableSaveFunctions } = require("./utils")
+const { TableSaveFunctions, hasTypeChanged } = require("./utils")
 
 exports.save = async function (ctx) {
   const appId = ctx.appId
@@ -21,6 +21,10 @@ exports.save = async function (ctx) {
     oldTable = await db.get(ctx.request.body._id)
   }
 
+  if (hasTypeChanged(tableToSave, oldTable)) {
+    ctx.throw(400, "A column type has changed.")
+  }
+
   // saving a table is a complex operation, involving many different steps, this
   // has been broken out into a utility to make it more obvious/easier to manipulate
   const tableSaveFunctions = new TableSaveFunctions({
diff --git a/packages/server/src/api/controllers/table/utils.js b/packages/server/src/api/controllers/table/utils.js
index 1cca4c41d2..18caecab9b 100644
--- a/packages/server/src/api/controllers/table/utils.js
+++ b/packages/server/src/api/controllers/table/utils.js
@@ -8,7 +8,7 @@ const {
 const { isEqual } = require("lodash/fp")
 const { AutoFieldSubTypes, FieldTypes } = require("../../../constants")
 const { inputProcessing } = require("../../../utilities/rowProcessor")
-const { USERS_TABLE_SCHEMA } = require("../../../constants")
+const { USERS_TABLE_SCHEMA, SwitchableTypes } = require("../../../constants")
 const {
   isExternalTable,
   breakExternalTableId,
@@ -335,4 +335,21 @@ exports.foreignKeyStructure = (keyName, meta = null) => {
   return structure
 }
 
+exports.hasTypeChanged = (table, oldTable) => {
+  if (!oldTable) {
+    return false
+  }
+  for (let [key, field] of Object.entries(oldTable.schema)) {
+    const oldType = field.type
+    if (!table.schema[key]) {
+      continue
+    }
+    const newType = table.schema[key].type
+    if (oldType !== newType && SwitchableTypes.indexOf(oldType) === -1) {
+      return true
+    }
+  }
+  return false
+}
+
 exports.TableSaveFunctions = TableSaveFunctions
diff --git a/packages/server/src/constants/index.js b/packages/server/src/constants/index.js
index 80c62cd02e..beac18dd3a 100644
--- a/packages/server/src/constants/index.js
+++ b/packages/server/src/constants/index.js
@@ -45,6 +45,13 @@ exports.FieldTypes = {
   INTERNAL: "internal",
 }
 
+exports.SwitchableTypes = [
+  exports.FieldTypes.STRING,
+  exports.FieldTypes.OPTIONS,
+  exports.FieldTypes.NUMBER,
+  exports.FieldTypes.BOOLEAN,
+]
+
 exports.RelationshipTypes = {
   ONE_TO_MANY: "one-to-many",
   MANY_TO_ONE: "many-to-one",
diff --git a/packages/server/src/integrations/base/sqlTable.ts b/packages/server/src/integrations/base/sqlTable.ts
index 974f395063..509af00955 100644
--- a/packages/server/src/integrations/base/sqlTable.ts
+++ b/packages/server/src/integrations/base/sqlTable.ts
@@ -30,7 +30,7 @@ function generateSchema(
     // skip things that are already correct
     const oldColumn = oldTable ? oldTable.schema[key] : null
     if (
-      (oldColumn && oldColumn.type === column.type) ||
+      (oldColumn && oldColumn.type) ||
       (primaryKey === key && !isJunction)
     ) {
       continue