completed error move.

src/data/mod.rs

@@ -1,6 +1,6 @@
 pub mod id;
 mod record;
-mod table;
+pub mod table;
 
 use crate::{
     data::table::Table,
@@ -47,8 +47,8 @@ impl Database {
     fn add_table(&mut self, name: &str, table: Table) -> Result<(), MTTError> {
         match self.tables.get(name) {
             Some(_) => {
-                let error = ErrorType::TableRecordInvalidFieldName(name.to_string());
-                return Err(MTTError::new(error));
+                let err = DBError::DuplicateTable(name.to_string());
+                return Err(err.into());
             }
             None => {}
         }