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

src/db/SQLHelper.cpp

@@ -0,0 +1,45 @@
+//
+// Created by Krad on 2021/10/11.
+//
+
+#include "SQLHelper.h"
+
+#include <QSqlDatabase>
+#include <QSqlQuery>
+QSqlDatabase* SQLHelper::defaultDatabase= nullptr;
+QHash<QString,CenterAlignSqlTableModel*>* SQLHelper::cache= new QHash<QString,CenterAlignSqlTableModel*>;
+bool SQLHelper::Open() {
+    if (defaultDatabase) return true;
+    defaultDatabase=  new QSqlDatabase(QSqlDatabase::addDatabase("QSQLITE", "USCTDB"));
+    defaultDatabase->setDatabaseName("USCTDB.data");
+    return defaultDatabase->open();
+}
+
+bool SQLHelper::Open(QSqlDatabase *base) {
+    if(base && base != defaultDatabase){
+        defaultDatabase = base;
+    }
+    return defaultDatabase->open();
+}
+
+void SQLHelper::Close() {
+    for(auto item : cache->values())
+    {
+        delete item;
+    }
+    cache->clear();
+    if(defaultDatabase->isValid() && defaultDatabase->isOpen())
+    {
+        defaultDatabase->close();
+        delete defaultDatabase;
+        defaultDatabase = nullptr;
+    }
+}
+
+QSqlTableModel* SQLHelper::getTable(const QString &tableName) {
+    if (cache->contains(tableName)) return (*cache)[tableName];
+    CenterAlignSqlTableModel *model = new CenterAlignSqlTableModel(nullptr,*defaultDatabase);
+    model->setTable(tableName);
+    (*cache)[tableName] = model;
+    return (*cache)[tableName];
+}