Polish oracle plugin to make DBType accurate (#32)

Author: pg-yang

oracle-10.x-plugin/src/main/java/io/skywalking/apm/plugin/jdbc/oracle/PreparedStatementExecuteMethodsInterceptor.java

@@ -50,7 +50,7 @@ public final void beforeMethod(EnhancedInstance objInst, Method method, Object[]
         if (cacheObject != null && cacheObject.getConnectionInfo() != null) {
             ConnectionInfo connectInfo = cacheObject.getConnectionInfo();
             AbstractSpan span = ContextManager.createExitSpan(buildOperationName(connectInfo, method.getName(), cacheObject.getStatementName()), connectInfo.getDatabasePeer());
-            Tags.DB_TYPE.set(span, "sql");
+            Tags.DB_TYPE.set(span, connectInfo.getDBType());
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
             Tags.DB_STATEMENT.set(span, cacheObject.getSql());
             span.setComponent(connectInfo.getComponent());

oracle-10.x-plugin/src/main/java/io/skywalking/apm/plugin/jdbc/oracle/StatementExecuteMethodsInterceptor.java

@@ -38,7 +38,7 @@ public void beforeMethod(EnhancedInstance objInst, Method method, Object[] allAr
             ConnectionInfo connectInfo = cacheObject.getConnectionInfo();
 
             AbstractSpan span = ContextManager.createExitSpan(buildOperationName(connectInfo, method.getName(), cacheObject.getStatementName()), connectInfo.getDatabasePeer());
-            Tags.DB_TYPE.set(span, "sql");
+            Tags.DB_TYPE.set(span, connectInfo.getDBType());
             Tags.DB_INSTANCE.set(span, connectInfo.getDatabaseName());
 
             String sql = "";