App-mgt store mapping validation

components/application-mgt/org.wso2.carbon.device.application.mgt.core/src/main/java/org/wso2/carbon/device/application/mgt/core/dao/impl/subscription/GenericSubscriptionDAOImpl.java

@@ -30,14 +30,23 @@ public class GenericSubscriptionDAOImpl extends AbstractDAOImpl implements Subsc
     private static Log log = LogFactory.getLog(GenericSubscriptionDAOImpl.class);
 
     @Override
-    public int addDeviceApplicationMapping(String deviceIdentifier, String applicationUUID, boolean installed) throws ApplicationManagementException {
+    public int addDeviceApplicationMapping(String deviceIdentifier, String applicationUUID, boolean installed) throws
+            ApplicationManagementException {
         Connection conn;
         PreparedStatement stmt = null;
         ResultSet rs = null;
         int mappingId = -1;
         try {
             conn = this.getDBConnection();
-            String sql = "INSERT INTO APPM_DEVICE_APPLICATION_MAPPING (DEVICE_IDENTIFIER, APPLICATION_UUID, " +
+            String sql = "SELECT ID FROM APPM_DEVICE_APPLICATION_MAPPING WHERE DEVICE_IDENTIFIER = ? AND " +
+                    "APPLICATION_UUID = ?";
+            stmt = conn.prepareStatement(sql);
+            stmt.setString(1, deviceIdentifier);
+            stmt.setString(2, applicationUUID);
+            rs = stmt.executeQuery();
+
+            if (!rs.next()) {
+                sql = "INSERT INTO APPM_DEVICE_APPLICATION_MAPPING (DEVICE_IDENTIFIER, APPLICATION_UUID, " +
                         "INSTALLED) VALUES (?, ?, ?)";
                 stmt = conn.prepareStatement(sql, new String[]{"id"});
                 stmt.setString(1, deviceIdentifier);
@@ -50,6 +59,11 @@ public class GenericSubscriptionDAOImpl extends AbstractDAOImpl implements Subsc
                     mappingId = rs.getInt(1);
                 }
                 return mappingId;
+            } else {
+                log.warn("Device[" + deviceIdentifier + "] application[" + applicationUUID + "] mapping already " +
+                        "exists in the DB");
+                return -1;
+            }
         } catch (SQLException e) {
             throw new ApplicationManagementException("Error occurred while adding device application mapping to DB", e);
         } finally {

features/application-mgt/org.wso2.carbon.device.application.mgt.server.feature/src/main/resources/dbscripts/cdm/application-mgt/mysql.sql

@@ -400,8 +400,9 @@ CREATE TABLE IF NOT EXISTS `APPM_DEVICE_APPLICATION_MAPPING` (
   `INSTALLED` BOOLEAN NOT NULL,
   `SENT_AT` DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
   PRIMARY KEY (ID),
-  CONSTRAINT fk_appm_application FOREIGN KEY (`APPLICATION_UUID`) REFERENCES
-  APPM_APPLICATION (`UUID`) ON DELETE NO ACTION ON UPDATE NO ACTION
+  CONSTRAINT `fk_appm_application` FOREIGN KEY (`APPLICATION_UUID`) REFERENCES
+  APPM_APPLICATION (`UUID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
+  UNIQUE KEY `device_app_mapping` (`DEVICE_IDENTIFIER`, `APPLICATION_UUID`)
 ) ENGINE = InnoDB;
 
 SET SQL_MODE=@OLD_SQL_MODE;