Add SQLHelper and CenterAlignSqlTableModel. The CenterAlignSqlTableModel only make the cell text align center.

src/db/CenterAlignSqlTableModel.h

@@ -0,0 +1,25 @@
+//
+// Created by Krad on 2021/10/11.
+//
+
+#ifndef GUI_CENTERALIGNSQLTABLEMODEL_H
+#define GUI_CENTERALIGNSQLTABLEMODEL_H
+
+#include <QSqlTableModel>
+class CenterAlignSqlTableModel:public QSqlTableModel {
+    Q_OBJECT
+public:
+    explicit CenterAlignSqlTableModel(QObject *parent = nullptr, QSqlDatabase db = QSqlDatabase()):QSqlTableModel(parent,db){};
+    ~CenterAlignSqlTableModel(){};
+protected:
+    QVariant data(const QModelIndex& index, int role) const override {
+        if (index.column() >0 && role == Qt::TextAlignmentRole) {
+            return Qt::AlignCenter;
+        } else {
+            return QSqlTableModel::data(index,role);
+        }
+    }
+};
+
+
+#endif //GUI_CENTERALIGNSQLTABLEMODEL_H