(improvement)(semantic) Supply and compatible with mysql demo data (#464)

Co-authored-by: jolunoluo

semantic/api/src/main/java/com/tencent/supersonic/semantic/api/model/request/DatabaseReq.java

@@ -36,8 +36,8 @@ public class DatabaseReq {
 
     private List<String> viewers = Lists.newArrayList();
 
-    public String getUrl() {
-        if (type.equalsIgnoreCase(DataTypeEnum.H2.getFeature())) {
+    public String getConnectUrl() {
+        if (StringUtils.isNotBlank(url)) {
             return url;
         }
         String databaseUrl = database;