diff --git a/routes/(apps)/mobility/(_islands)/EditMobility.tsx b/routes/(apps)/mobility/(_islands)/EditMobility.tsx
index 7438518..fe3f9ef 100644
--- a/routes/(apps)/mobility/(_islands)/EditMobility.tsx
+++ b/routes/(apps)/mobility/(_islands)/EditMobility.tsx
@@ -13,7 +13,7 @@ interface Promotion {
 }
 
 interface Mobility {
-  id: number;
+  id: number | null;
   studentId: string;
   startDate: string | null;
   endDate: string | null;
@@ -63,7 +63,20 @@ export default function EditMobility() {
 
       const updatedMobilities = prevData.mobilities?.map((mobility) => {
         if (mobility.studentId === studentId) {
-          return { ...mobility, [field]: value };
+          const updatedMobility = { ...mobility, [field]: value };
+
+          if (field === "startDate" || field === "endDate") {
+            const startDate = new Date(updatedMobility.startDate || "");
+            const endDate = new Date(updatedMobility.endDate || "");
+            if (startDate && endDate && startDate <= endDate) {
+              const weeks = Math.ceil((endDate.getTime() - startDate.getTime()) / (7 * 24 * 60 * 60 * 1000));
+              updatedMobility.weeksCount = weeks;
+            } else {
+              updatedMobility.weeksCount = null;
+            }
+          }
+
+          return updatedMobility;
         }
         return mobility;
       }) || [];
@@ -86,7 +99,7 @@ export default function EditMobility() {
 
       if (response.ok) {
         alert("Data saved successfully!");
-        window.location.reload(); // Refresh the page to load updated data
+        window.location.reload();
       } else {
         throw new Error(`Failed to save data: ${response.statusText}`);
       }
@@ -131,6 +144,7 @@ export default function EditMobility() {
                 ?.filter((student) => student.promotionId === promo.id)
                 .map((student) => {
                   const mobility = data.mobilities?.find((mob) => mob.studentId === student.id) || {
+                    id: null,
                     studentId: student.id,
                     startDate: null,
                     endDate: null,
@@ -159,15 +173,7 @@ export default function EditMobility() {
                           onChange={(e) => handleChange(student.id, "endDate", e.target.value)}
                         />
                       </td>
-                      <td>
-                        <input
-                          type="number"
-                          value={mobility.weeksCount || ""}
-                          onChange={(e) =>
-                            handleChange(student.id, "weeksCount", Number(e.target.value) || null)
-                          }
-                        />
-                      </td>
+                      <td>{mobility.weeksCount ?? "N/A"}</td>
                       <td>
                         <input
                           type="text"
diff --git a/routes/(apps)/mobility/api/insert_mobility.ts b/routes/(apps)/mobility/api/insert_mobility.ts
index 365e79b..5eb0f0e 100644
--- a/routes/(apps)/mobility/api/insert_mobility.ts
+++ b/routes/(apps)/mobility/api/insert_mobility.ts
@@ -65,15 +65,30 @@ export const handler: Handlers = {
 
       const connection = new Database("databases/data/mobility.db", { create: false });
 
+      console.log("Attaching students database...");
+      connection.run("ATTACH DATABASE 'databases/data/students.db' AS students");
+      console.log("Students database attached successfully.");
+
+      const testStudents = connection.prepare("SELECT COUNT(*) AS count FROM students.students").get();
+      console.log(`Students table accessible, total records: ${testStudents.count}`);
+
       const insertQuery = connection.prepare(
         `INSERT INTO mobility (
-          studentId, startDate, endDate, weeksCount, destinationCountry, destinationName, mobilityStatus
+          id, studentId, startDate, endDate, weeksCount, destinationCountry, destinationName, mobilityStatus
         )
-        VALUES (?, ?, ?, ?, ?, ?, ?)`
+        VALUES (?, ?, ?, ?, ?, ?, ?, ?)
+        ON CONFLICT(id) DO UPDATE SET
+          startDate = excluded.startDate,
+          endDate = excluded.endDate,
+          weeksCount = excluded.weeksCount,
+          destinationCountry = excluded.destinationCountry,
+          destinationName = excluded.destinationName,
+          mobilityStatus = excluded.mobilityStatus`
       );
-
+      
       for (const mobility of data) {
         const {
+          id = null,
           studentId,
           startDate,
           endDate,
@@ -82,12 +97,35 @@ export const handler: Handlers = {
           destinationName,
           mobilityStatus = "N/A",
         } = mobility;
-
+      
+        let calculatedWeeksCount = weeksCount;
+        if (startDate && endDate) {
+          const start = new Date(startDate);
+          const end = new Date(endDate);
+          if (start <= end) {
+            calculatedWeeksCount = Math.ceil((end.getTime() - start.getTime()) / (7 * 24 * 60 * 60 * 1000));
+          } else {
+            calculatedWeeksCount = null;
+          }
+        }
+      
+        console.log(`Inserting/Updating mobility for studentId: ${studentId}`);
+      
+        const studentExists = connection
+          .prepare(`SELECT COUNT(*) AS count FROM students.students WHERE userId = ?`)
+          .get(studentId);
+      
+        if (studentExists.count === 0) {
+          console.warn(`Skipping mobility for unknown studentId: ${studentId}`);
+          continue;
+        }
+      
         insertQuery.run(
+          id,
           studentId,
           startDate,
           endDate,
-          weeksCount,
+          calculatedWeeksCount,
           destinationCountry,
           destinationName,
           mobilityStatus
@@ -95,12 +133,11 @@ export const handler: Handlers = {
       }
 
       connection.close();
-
-      console.log("Mobility data inserted successfully");
-      return new Response("Data inserted successfully", { status: 201 });
+      console.log("Mobility data inserted/updated successfully.");
+      return new Response("Data inserted/updated successfully", { status: 200 });
     } catch (error) {
       console.error("Error inserting mobility data:", error);
-      return new Response("Failed to insert data", { status: 500 });
+      return new Response("Failed to insert/update data", { status: 500 });
     }
   },
-};
+};
\ No newline at end of file
diff --git a/routes/(apps)/students/(_islands)/ConsultStudents.tsx b/routes/(apps)/students/(_islands)/ConsultStudents.tsx
index da24056..c92ba5e 100644
--- a/routes/(apps)/students/(_islands)/ConsultStudents.tsx
+++ b/routes/(apps)/students/(_islands)/ConsultStudents.tsx
@@ -6,12 +6,11 @@ interface Promotion {
 }
 
 interface Student {
-  id: number;
+  userId: string;
   firstName: string;
   lastName: string;
   mail: string;
   promotionId: number;
-  promotionName: string;
 }
 
 export default function ConsultStudents() {
@@ -27,6 +26,7 @@ export default function ConsultStudents() {
         }
 
         const result = await response.json();
+        console.log("Fetched data:", result);
         setData(result);
       } catch (err) {
         console.error("Error fetching data:", err);
@@ -43,7 +43,7 @@ export default function ConsultStudents() {
       {error && <p className="error">{error}</p>}
       {data?.promotions.map((promo) => (
         <div key={promo.id}>
-          <h3>Promotion: {promo.id}</h3> 
+          <h3>Promotion: {promo.name}</h3>
           <table>
             <thead>
               <tr>
@@ -57,8 +57,8 @@ export default function ConsultStudents() {
               {data.students
                 .filter((student) => student.promotionId === promo.id)
                 .map((student) => (
-                  <tr key={student.id}>
-                    <td>{student.id}</td>
+                  <tr key={student.userId}>
+                    <td>{student.userId}</td>
                     <td>{student.firstName}</td>
                     <td>{student.lastName}</td>
                     <td>{student.mail}</td>
diff --git a/routes/(apps)/students/(_islands)/UploadStudents.tsx b/routes/(apps)/students/(_islands)/UploadStudents.tsx
index 10ed4e2..e84e951 100644
--- a/routes/(apps)/students/(_islands)/UploadStudents.tsx
+++ b/routes/(apps)/students/(_islands)/UploadStudents.tsx
@@ -33,10 +33,12 @@ export default function UploadStudents() {
         for (const sheetName of workbook.SheetNames) {
           const sheet = workbook.Sheets[sheetName];
           const data = XLSX.utils.sheet_to_json(sheet, {
-            header: ["Nom", "Prénom", "Mail"], 
+            header: ["Identifiant", "Nom", "Prénom", "Mail"],
             range: 1, // Ignorer les en-têtes
           });
 
+          console.log(`Data from sheet ${sheetName}:`, data);
+
           const response = await fetch("/students/api/insert_students", {
             method: "POST",
             headers: { "Content-Type": "application/json" },
diff --git a/routes/(apps)/students/api/insert_students.ts b/routes/(apps)/students/api/insert_students.ts
index 98b11cb..c6c70fc 100644
--- a/routes/(apps)/students/api/insert_students.ts
+++ b/routes/(apps)/students/api/insert_students.ts
@@ -1,4 +1,5 @@
 import { Handlers } from "$fresh/server.ts";
+import { Database } from "@db/sqlite";
 import connect from "$root/databases/connect.ts";
 
 export const handler: Handlers = {
@@ -7,7 +8,7 @@ export const handler: Handlers = {
       using connection = connect("students");
 
       const promotions = connection.database.prepare(
-        "select id from promotions",
+        "select id, name from promotions",
       ).all();
 
       const students = connection.database
@@ -30,7 +31,7 @@ export const handler: Handlers = {
   },
 
   async POST(request) {
-    console.log("API /mobility/api/insert_students called");
+    console.log("API /students/api/insert_students called");
 
     try {
       const body = await request.json();
@@ -48,7 +49,7 @@ export const handler: Handlers = {
         "INSERT OR IGNORE INTO promotions (name) VALUES (?)",
       ).run(promoName);
 
-      const promoIdRow: {id: string} = connection.database
+      const promoIdRow: { id: number } = connection.database
         .prepare("SELECT id FROM promotions WHERE name = ?")
         .get(promoName)!;
       const promoId = promoIdRow.id;
@@ -56,12 +57,20 @@ export const handler: Handlers = {
       console.log(`Promotion ID for "${promoName}":`, promoId);
 
       const insertQuery = connection.database.prepare(
-        "INSERT INTO students (firstName, lastName, mail, promotionId) VALUES (?, ?, ?, ?)",
+        `INSERT INTO students 
+        (userId, firstName, lastName, mail, promotionId) 
+        VALUES (?, ?, ?, ?, ?)`,
       );
 
       for (const student of data) {
         console.log("Inserting student:", student);
-        insertQuery.run(student.Nom, student["Prénom"], student.Mail, promoId);
+        insertQuery.run(
+          student.Identifiant,
+          student.Nom,
+          student["Prénom"],
+          student.Mail,
+          promoId,
+        );
       }
 
       console.log("All data inserted successfully");