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v4.4.5 to v4.5.1 migration guide

The Strapi v4.4.5 to v4.5.1 migration guide upgrades v4.4.5 to v4.5.1. We introduced unique indexes on relationship tables and the application will not start if there are duplicated relationships. The migration guide consists of:

  • Upgrading the application dependencies
  • Installing database migration script (optional)
  • Reinitializing the application

Plugins extension that create custom code or modify existing code, will need to be updated and compared to the changes in the repository. Not updating the plugin extensions could break the application.

Upgrading the application dependencies to 4.5.1

☑️ Prerequisites

Stop the server before starting the upgrade.

  1. Upgrade all of the Strapi packages in package.json to 4.5.1:

    path: package.json

    // ...
    "dependencies": {
    "@strapi/strapi": "4.5.1",
    "@strapi/plugin-users-permissions": "4.5.1",
    "@strapi/plugin-i18n": "4.5.1"
    // ...
  2. Save the edited package.json file.

  3. Run the install command:

    Install the upgraded version:

    💡 Tip

    If the operation doesn't work, try removing your yarn.lock or package-lock.json. If that doesn't help, remove the node_modules folder as well and try again.

Installing database migration script (optional)

This step is only required if you have relationship duplicates in your application. If you have them, the application will not start and you will see an error message in the terminal similar to:

error: alter table <SOME_TABLE> add constraint <SOME_TABLE_INDEX>
unique (<COLUMN_NAME>, <COLUMN_NAME>) - could not create unique index <SOME_TABLE>

To remove the duplicated relationships easily, the following migration script file was created. It will automatically remove duplicates of any relationship in the database and will be executed only once at the next launch of Strapi.

To prepare the migration:

  1. Make a backup of the database in case something unexpected happens.
  2. Make sure you are migrating from a version greater than or equal to 4.4.5. If not, please migrate to the 4.4.5 version first, otherwise this script will not work.
  3. In the ./database/migrations folder, create a file named 2022.11.16T00.00.00.remove_duplicated_relationships.js.
  4. Copy and paste the following code into the previously created file:
'use strict';

* Get the link tables names that need to be updated
const getLinkTables = ({ strapi }) => {
const contentTypes = strapi.db.metadata;
const tablesToUpdate = {};

contentTypes.forEach((contentType) => {
// Get attributes
const attributes = contentType.attributes;

// For each relation type, add the joinTable name to tablesToUpdate
Object.values(attributes).forEach((attribute) => {
if (
attribute.type === 'relation' &&
attribute.joinTable &&
!attribute.relation.startsWith('morph') // Ignore polymorphic relations
) {
tablesToUpdate[] = attribute.joinTable;

return Object.values(tablesToUpdate);

async function up(trx) {
const linkTablesToUpdate = getLinkTables({ strapi });

// Remove duplicates from link tables
for (const table of linkTablesToUpdate) {
const tableExists = await trx.schema.hasTable(;
if (!tableExists) continue;`Deleting duplicates of table ${}...`);

try {
// Query to delete duplicates from a link table
let query = `
FROM ?? as t1 JOIN ?? as t2
ON <
const pivotWhereParams = [];

// For each pivot column, add a on condition to the query
table.pivotColumns.forEach(column => {
query += ` AND t1.?? = t2.??`;
pivotWhereParams.push(column, column);

// Create temporary table with the ids of the repeated rows
await trx.raw(query, [,, ...pivotWhereParams]);

// Delete repeated rows from the original table
await trx.raw(`DELETE FROM ?? WHERE id in (SELECT * FROM tmp)`, []);
} finally {
// Drop temporary table
await trx.raw(`DROP TABLE IF EXISTS tmp `);

async function down() {}

module.exports = { up, down };
  1. Save the file.

Rebuild the application

Run the following command in your project root directory to rebuild Strapi's admin panel:

yarn build

Restart the application

Run the following command in your project root directory to restart the application:

yarn develop