17 files changed, 588 insertions, 62 deletions

diff --git a/core/CMakeLists.txt b/core/CMakeLists.txt
index 0432ed1..02fa74a 100644
--- a/core/CMakeLists.txt
+++ b/core/CMakeLists.txt
@@ -34,6 +34,7 @@ set(ENTRYPOINT_MODULE_SOURCES
 )
 
 add_source_group(MODEL_MODULE_SOURCES
+	src/Model/Filter.cpp
 	src/Model/GlobalStates.cpp
 	src/Model/Items.cpp
 	src/Model/Project.cpp
diff --git a/core/locale/zh_CN.json b/core/locale/zh_CN.json
index 917d2f3..188ec4f 100644
--- a/core/locale/zh_CN.json
+++ b/core/locale/zh_CN.json
@@ -1,13 +1,15 @@
 {
 	"$localized_name": "中文 - 中国",
 	"Generic.Error": "错误",
+	"Generic.Add": "\uf067 新建",
+	"Generic.Edit": "\uf044 编辑",
+	"Generic.Delete": "\uf1f8 删除",
 	"Generic.Dialog.Confirm": "确定",
 	"Generic.Dialog.Cancel": "取消",
 	"MainWindow.Tab.Settings": "\uf013 设置",
 	"MainWindow.Tab.Project": "\uf15b 项目",
 	"MainWindow.Tab.DatabaseView": "\uf1c0 数据",
 	"MainWindow.Tab.Items": "\uf466 物品",
-	"MainWindow.Tab.Exports": "\uf56e 导出",
 	"Project.New": "新建项目...",
 	"Project.New.DialogTitle": "新建项目向导",
 	"Project.New.Name": "项目名称",
@@ -27,11 +29,16 @@
 	"ActiveProject.OpenInFilesystem": "\uf07b 在文件系统中打开",
 	"ActiveProject.Info.Name": "项目名称：",
 	"ActiveProject.Info.Path": "项目路径：",
-	"Item.Add": "\uf067 新建",
+	"Database.SalesView.TabName": "销售",
+	"Database.SalesView.Edit.DialogTitle": "编辑销售记录",
+	"Database.PurchasesView.TabName": "采购",
+	"Database.DeliveriesView.TabName": "运输",
+	"Database.Column.Customer": "客户",
+	"Database.Column.Deadline": "交货期限",
+	"Database.Column.DeliveryTime": "交货时间",
+	"Database.Message.NotDelivered": "N/A",
 	"Item.Add.DialogTitle": "新建物品项",
-	"Item.Edit": "\uf044 编辑",
 	"Item.Edit.DialogTitle": "编辑物品项",
-	"Item.Delete": "\uf1f8 删除",
 	"Item.Delete.DialogTitle": "删除物品项",
 	"Item.Delete.DialogMessage": "确定删除该物品项吗？",
 	"Item.CategoryName.Product": "产品",
@@ -40,6 +47,8 @@
 	"Item.Column.Name": "名称",
 	"Item.Column.Description": "描述",
 	"Item.Column.Email": "邮箱",
+	"Item.Column.Stock": "库存",
+	"Item.Column.Price": "价格",
 	"Item.EmptyNameError": "产品名不能为空",
 	"Item.DuplicateNameError": "产品名已被占用",
 }
\ No newline at end of file
diff --git a/core/src/Model/Filter.cpp b/core/src/Model/Filter.cpp
new file mode 100644
index 0000000..1e4b31b
--- /dev/null
+++ b/core/src/Model/Filter.cpp
@@ -0,0 +1 @@
+#include "Filter.hpp"
diff --git a/core/src/Model/Filter.hpp b/core/src/Model/Filter.hpp
new file mode 100644
index 0000000..53995c1
--- /dev/null
+++ b/core/src/Model/Filter.hpp
@@ -0,0 +1,5 @@
+#pragma once
+
+class TableRowsFilter {
+	// TODO
+};
diff --git a/core/src/Model/Items.cpp b/core/src/Model/Items.cpp
index 2951666..02a4516 100644
--- a/core/src/Model/Items.cpp
+++ b/core/src/Model/Items.cpp
@@ -8,6 +8,13 @@ void ProductItem::SetDescription(std::string description) {
 	mDescription = std::move(description);
 }
 
+int ProductItem::GetPrice() const {
+	return mPrice;
+}
+void ProductItem::SetPrice(int price) {
+	mPrice = price;
+}
+
 int ProductItem::GetStock() const {
 	return mStock;
 }
@@ -19,12 +26,14 @@ void ProductItem::SetStock(int stock) {
 Json::Value ProductItem::Serialize() const {
 	Json::Value elm;
 	elm["Description"] = mDescription;
+	elm["Price"] = mPrice;
 	elm["Stock"] = mStock;
 	return elm;
 }
 
 void ProductItem::Deserialize(const Json::Value& elm) {
 	mDescription = elm["Description"].asString();
+	mPrice = elm["Price"].asInt();
 	mStock = elm["Stock"].asInt();
 }
 
diff --git a/core/src/Model/Items.hpp b/core/src/Model/Items.hpp
index 14b62f3..1289be6 100644
--- a/core/src/Model/Items.hpp
+++ b/core/src/Model/Items.hpp
@@ -175,6 +175,7 @@ public:
 class ProductItem : public ItemBase<ProductItem> {
 private:
 	std::string mDescription;
+	int mPrice = 0;
 	int mStock = 0;
 
 public:
@@ -182,6 +183,11 @@ public:
 
 	const std::string& GetDescription() const;
 	void SetDescription(std::string description);
+	/// Get the price of this item in US cents.
+	int GetPrice() const;
+	void SetPrice(int price);
+	/// Get the current number of this product in warehouse.
+	/// This is a housekeeping field and shouldn't be editable by the user from the UI.
 	int GetStock() const;
 	void SetStock(int stock);
 
diff --git a/core/src/Model/Project.cpp b/core/src/Model/Project.cpp
index c20e0c8..2a79e3f 100644
--- a/core/src/Model/Project.cpp
+++ b/core/src/Model/Project.cpp
@@ -82,6 +82,14 @@ void Project::SetName(std::string name) {
 	mName = std::move(name);
 }
 
+const TransactionDatabase& Project::GetDatabase() const {
+	return mDb;
+}
+
+TransactionDatabase& Project::GetDatabase() {
+	return mDb;
+}
+
 Json::Value Project::Serialize() {
 	Json::Value root(Json::objectValue);
 
diff --git a/core/src/Model/Project.hpp b/core/src/Model/Project.hpp
index 8d437ea..dca10d0 100644
--- a/core/src/Model/Project.hpp
+++ b/core/src/Model/Project.hpp
@@ -39,6 +39,9 @@ public:
 	const std::string& GetName() const;
 	void SetName(std::string name);
 
+	const TransactionDatabase& GetDatabase() const;
+	TransactionDatabase& GetDatabase();
+
 	Json::Value Serialize();
 	void WriteToDisk();
 };
diff --git a/core/src/Model/TransactionDatabase.cpp b/core/src/Model/TransactionDatabase.cpp
index c28db0d..766727d 100644
--- a/core/src/Model/TransactionDatabase.cpp
+++ b/core/src/Model/TransactionDatabase.cpp
@@ -4,38 +4,157 @@
 
 #include <filesystem>
 #include <stdexcept>
-#include <string>
 
 namespace fs = std::filesystem;
 
-static bool TableExists(sqlite3* db, const char* table, const char* column = nullptr) {
-	return sqlite3_table_column_metadata(db, nullptr, table, column, nullptr, nullptr, nullptr, nullptr, nullptr) == SQLITE_OK;
+SalesTable::SalesTable(TransactionDatabase& db)
+	// language=SQLite
+	: GetRowsStatement(db.GetSQLite(), R"""(
+SELECT * FROM Sales WHERE rowid >= ? AND rowid < ?
+)""")
+	// language=SQLite
+	// TODO
+	, FilterRowsStatement(db.GetSQLite(), R"""(
+)""") {
+}
+
+int SalesTable::GetEntryCont() const {
+	// TODO
+	return 0;
+}
+
+DeliveryTable::DeliveryTable(TransactionDatabase& db) {
+}
+
+PurchasesTable::PurchasesTable(TransactionDatabase& db) {
+}
+
+static std::string GetDatabaseFilePath(const Project& project) {
+	auto dbsDir = project.GetPath() / "databases";
+	fs::create_directories(dbsDir);
+
+	auto dbFile = dbsDir / "transactions.sqlite3";
+	return dbFile.string();
 }
 
 TransactionDatabase::TransactionDatabase(Project& project)
 	: mProject{ &project }
-	, mDatabase{ nullptr } {
+	, mDb(GetDatabaseFilePath(project), SQLite::OPEN_READWRITE)
+	, mSales(*this)
+	, mPurchases(*this)
+	, mDeliveries(*this) {
+	// Schema
+	// - Customer: the customer item ID
+	// - Deadline: unix epoch time of order deadline
+	// - DeliveryTime: the time this order was completed (through a set of deliveries)
+	if (!mDb.tableExists("Sales")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE Sales(
+	INT PRIMARY KEY,
+	Customer INT,
+	Deadline DATETIME,
+	DeliveryTime DATETIME
+);
+)""");
+	}
+
+	if (!mDb.tableExists("SalesItems")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE SalesItems(
+	SaleId INT,
+	ItemId INT,
+	Count INT
+);
+)""");
+	}
 
-	fs::path dbDir = project.GetPath() / "databases";
-	fs::create_directories(dbDir);
+	// Schema
+	// - Factory: the factory id,
+	// - OrderTime: the time this order was made
+	// - DeliveryTime: the time this order was completed (through a set of deliveries)
+	if (!mDb.tableExists("Purchases")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE Purchases(
+	INT PRIMARY KEY,
+	Factory INT,
+	OrderTime DATETIME,
+	DeliveryTime DATETIME
+);
+)""");
+	}
+
+	if (!mDb.tableExists("PurchasesItems")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE PurchasesItems(
+	PurchaseId INT,
+	ItemId INT,
+	Count INT
+);
+)""");
+	}
 
-	fs::path dbPath = dbDir / "transactions.sqlite3";
-#if PLATFORM_WIN32
-	if (int rc = sqlite3_open16(dbPath.c_str(), &mDatabase); rc) {
-#else
-	if (int rc = sqlite3_open(transactionDbPath.c_str(), &mDatabase); rc) {
-#endif
-		sqlite3_close(mDatabase);
+	// Schema
+	// - SendTime: unix epoch time of sending to delivery
+	// - ArriveTime: unix epoch time of delivery arrived at warehouse; 0 if not arrived yet
+	// - AssociatedOrder: rowid of the order that this delivery is completing (which table: Outgoing=true -> Sales, Outgoing=false -> Purchases)
+	// - Outgoing: true if the delivery is from warehouse to customer; false if the delivery is from factory to warehouse
+	if (!mDb.tableExists("Deliveries")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE Deliveries(
+	INT PRIMARY KEY,
+	SendTime DATETIME,
+	ArriveTime DATETIME,
+	AssociatedOrder INT,
+	Outgoing BOOLEAN
+);
+)""");
+	}
 
-		std::string message;
-		message += "Failed to open SQLite database for transactions. Error code: ";
-		message += rc;
-		message += ".";
-		throw std::runtime_error(message);
+	if (!mDb.tableExists("DeliveriesItems")) {
+		// language=SQLite
+		mDb.exec(R"""(
+CREATE TABLE DeliveriesItems(
+	DeliveryId INT,
+	ItemId INT,
+	Count INT
+);
+)""");
 	}
 }
 
-TransactionDatabase::~TransactionDatabase() {
-	sqlite3_close(mDatabase);
-	mDatabase = nullptr;
+const SQLite::Database& TransactionDatabase::GetSQLite() const {
+	return mDb;
+}
+
+SQLite::Database& TransactionDatabase::GetSQLite() {
+	return mDb;
+}
+
+const SalesTable& TransactionDatabase::GetSales() const {
+	return mSales;
+}
+
+SalesTable& TransactionDatabase::GetSales() {
+	return mSales;
+}
+
+const PurchasesTable& TransactionDatabase::GetPurchases() const {
+	return mPurchases;
+}
+
+PurchasesTable& TransactionDatabase::GetPurchases() {
+	return mPurchases;
+}
+
+const DeliveryTable& TransactionDatabase::GetDeliveries() const {
+	return mDeliveries;
+}
+
+DeliveryTable& TransactionDatabase::GetDeliveries() {
+	return mDeliveries;
 }
diff --git a/core/src/Model/TransactionDatabase.hpp b/core/src/Model/TransactionDatabase.hpp
index 191a8b8..9c869c4 100644
--- a/core/src/Model/TransactionDatabase.hpp
+++ b/core/src/Model/TransactionDatabase.hpp
@@ -2,33 +2,49 @@
 
 #include "cplt_fwd.hpp"
 
-#include <sqlite3.h>
+#include <SQLiteCpp/Database.h>
+#include <SQLiteCpp/Statement.h>
 #include <cstdint>
 
-struct DeliveryId {
-	int64_t id;
-};
+class SalesTable {
+public:
+	SQLite::Statement GetRowsStatement;
+	SQLite::Statement FilterRowsStatement;
 
-class DeliveryTable {
-};
+public:
+	SalesTable(TransactionDatabase& db);
 
-class OrdersTable {
+	int GetEntryCont() const;
 };
 
 class PurchasesTable {
+public:
+	PurchasesTable(TransactionDatabase& db);
+};
+
+class DeliveryTable {
+public:
+	DeliveryTable(TransactionDatabase& db);
 };
 
 class TransactionDatabase {
 private:
 	Project* mProject;
-	sqlite3* mDatabase;
+	SQLite::Database mDb;
+	SalesTable mSales;
+	PurchasesTable mPurchases;
+	DeliveryTable mDeliveries;
 
 public:
 	TransactionDatabase(Project& project);
-	~TransactionDatabase();
 
-	TransactionDatabase(const TransactionDatabase&) = delete;
-	TransactionDatabase& operator=(const TransactionDatabase&) = delete;
-	TransactionDatabase(TransactionDatabase&&) = default;
-	TransactionDatabase& operator=(TransactionDatabase&&) = default;
+	const SQLite::Database& GetSQLite() const;
+	SQLite::Database& GetSQLite();
+
+	const SalesTable& GetSales() const;
+	SalesTable& GetSales();
+	const PurchasesTable& GetPurchases() const;
+	PurchasesTable& GetPurchases();
+	const DeliveryTable& GetDeliveries() const;
+	DeliveryTable& GetDeliveries()
 };
diff --git a/core/src/Model/fwd.hpp b/core/src/Model/fwd.hpp
index 2d8d2ec..e153923 100644
--- a/core/src/Model/fwd.hpp
+++ b/core/src/Model/fwd.hpp
@@ -1,5 +1,8 @@
 #pragma once
 
+// Filter.hpp
+class TableRowsFilter;
+
 // GlobalStates.hpp
 class GlobalStates;
 
@@ -16,4 +19,7 @@ class CustomerItem;
 class Project;
 
 // TransactionDatabase.hpp
+class SalesTable;
+class PurchasesTable;
+class DeliveryTable;
 class TransactionDatabase;
diff --git a/core/src/UI/Localization.hpp b/core/src/UI/Localization.hpp
index 86b7afc..f476458 100644
--- a/core/src/UI/Localization.hpp
+++ b/core/src/UI/Localization.hpp
@@ -12,15 +12,23 @@ public:
 	static std::unique_ptr<LocaleStrings> Instance;
 
 public:
+	/* Generic */
+
 	BasicTranslation Error{ "Generic.Error"sv };
+	BasicTranslation Add{ "Generic.Add"sv };
+	BasicTranslation Edit{ "Generic.Edit"sv };
+	BasicTranslation Delete{ "Generic.Delete"sv };
 	BasicTranslation DialogConfirm{ "Generic.Dialog.Confirm"sv };
 	BasicTranslation DialogCancel{ "Generic.Dialog.Cancel"sv };
 
-	BasicTranslation TabSettings{ "MainWindow.Tab.Settings"sv };
-	BasicTranslation TabProject{ "MainWindow.Tab.Project"sv };
-	BasicTranslation TabDatabaseView{ "MainWindow.Tab.DatabaseView"sv };
-	BasicTranslation TabItems{ "MainWindow.Tab.Items"sv };
-	BasicTranslation TabExport{ "MainWindow.Tab.Exports"sv };
+	/* Main window */
+
+	BasicTranslation SettingsTab{ "MainWindow.Tab.Settings"sv };
+	BasicTranslation ProjectTab{ "MainWindow.Tab.Project"sv };
+	BasicTranslation DatabaseViewTab{ "MainWindow.Tab.DatabaseView"sv };
+	BasicTranslation ItemsTab{ "MainWindow.Tab.Items"sv };
+
+	/* Project tab */
 
 	BasicTranslation NewProject{ "Project.New"sv };
 	BasicTranslation NewProjectDialogTitle{ "Project.New.DialogTitle"sv };
@@ -46,11 +54,24 @@ public:
 	BasicTranslation ActiveProjectName{ "ActiveProject.Info.Name"sv };
 	BasicTranslation ActiveProjectPath{ "ActiveProject.Info.Path"sv };
 
-	BasicTranslation AddItem{ "Item.Add"sv };
+	/* Database view tab */
+
+	BasicTranslation SalesViewTab{ "Database.SalesView.TabName"sv };
+	BasicTranslation EditSaleEntryDialogTitle{ "Database.SalesView.Edit.DialogTitle"sv };
+
+	BasicTranslation PurchasesViewTab{ "Database.PurchasesView.TabName"sv };
+
+	BasicTranslation DeliveriesViewTab{ "Database.DeliveriesView.TabName"sv };
+
+	BasicTranslation DatabaseCustomerColumn{ "Database.Column.Customer"sv };
+	BasicTranslation DatabaseDeadlineColumn{ "Database.Column.Deadline"sv };
+	BasicTranslation DatabaseDeliveryTimeColumn{ "Database.Column.DeliveryTime"sv };
+	BasicTranslation NotDeliveredMessage{ "Database.Message.NotDelivered"sv };
+
+	/* Items tab */
+
 	BasicTranslation AddItemDialogTitle{ "Item.Add.DialogTitle"sv };
-	BasicTranslation EditItem{ "Item.Edit"sv };
 	BasicTranslation EditItemDialogTitle{ "Item.Edit.DialogTitle"sv };
-	BasicTranslation DeleteItem{ "Item.Delete"sv };
 	BasicTranslation DeleteItemDialogTitle{ "Item.Delete.DialogTitle"sv };
 	BasicTranslation DeleteItemDialogMessage{ "Item.Delete.DialogMessage"sv };
 
@@ -61,6 +82,8 @@ public:
 	BasicTranslation ItemNameColumn{ "Item.Column.Name"sv };
 	BasicTranslation ItemDescriptionColumn{ "Item.Column.Description"sv };
 	BasicTranslation ItemEmailColumn{ "Item.Column.Email"sv };
+	BasicTranslation ItemStockColumn{ "Item.Column.Stock"sv };
+	BasicTranslation ItemPriceColumn{ "Item.Column.Price"sv };
 
 	BasicTranslation EmptyItemNameError{ "Item.EmptyNameError"sv };
 	BasicTranslation DuplicateItemNameError{ "Item.DuplicateNameError"sv };
diff --git a/core/src/UI/UI_DatabaseView.cpp b/core/src/UI/UI_DatabaseView.cpp
index 234aeaa..2b74918 100644
--- a/core/src/UI/UI_DatabaseView.cpp
+++ b/core/src/UI/UI_DatabaseView.cpp
@@ -1,9 +1,281 @@
 #include "UI.hpp"
 
+#include "Model/Project.hpp"
 #include "UI/Localization.hpp"
+#include "UI/States.hpp"
+#include "Utils/ScopeGuard.hpp"
+#include "cplt_fwd.hpp"
 
+#include <IconsFontAwesome.h>
+#include <SQLiteCpp/Statement.h>
 #include <imgui.h>
+#include <cstdint>
+#include <memory>
+#include <vector>
+
+namespace {
+
+// TODO move to Settings
+constexpr int kMaxEntriesPerPage = 20;
+
+class SaleEntry {
+public:
+	std::string Customer;
+	std::string Deadline;
+	std::string DeliveryTime;
+};
+
+class SalesViewTab {
+private:
+	Project* mProject;
+
+	/// Current active filter object, or \c nullptr.
+	std::unique_ptr<TableRowsFilter> mActiveFilter;
+
+	/// Inclusive.
+	/// \see mLastCachedRowId
+	int64_t mFirstCachedRowId;
+	/// Inclusive.
+	/// \see mFirstCachedRowId
+	int64_t mLastCachedRowId;
+
+	/// A cached, contiguous (row id of each entry is monotonically increasing, but not necessarily starts at 0) list ready-to-be-presented entries. May be incomplete.
+	std::vector<SaleEntry> mEntries;
+
+	// TODO this is very impractical (running filter in client code instead of letting SQLite doing it)
+	// Maybe simply cache a list of indices produced by a sql query?
+
+	/// A bitset of all active (should-be-displayed) entries based on current filter, updated whenever \c mActiveFilter is updated.
+	/// Should have the exact same size as \c entries.
+	std::vector<bool> mActiveEntries;
+
+	/// A cached list of index to entries that should be displayed on the current page.
+	std::vector<int> mCurrentPageEntries;
+
+	/// The current page the user is on.
+	int mCurrentPage;
+	/// Last possible page for the current set table and filter (inclusive).
+	int mLastPage;
+
+	/* UI states */
+
+	int mSelectedEntry;
+
+public:
+	void OnProjectChanged(Project* newProject) {
+		mProject = newProject;
+
+		mEntries.clear();
+		mCurrentPage = 0;
+		mLastPage = -1;
+
+		mSelectedEntry = -1;
+	}
+
+	void OnFilterChanged(std::unique_ptr<TableRowsFilter> filter) {
+		// TODO
+	}
+
+	void Draw() {
+		bool dummy = true;
+		auto ls = LocaleStrings::Instance.get();
+
+		if (ImGui::Button(ICON_FA_ARROW_LEFT, mCurrentPage == 0)) {
+			SetPage(mCurrentPage - 1);
+		}
+
+		ImGui::SameLine();
+		// +1 to convert from 0-based indices to 1-based, for human legibility
+		ImGui::Text("%d/%d", mCurrentPage + 1, mLastPage + 1);
+
+		ImGui::SameLine();
+		if (ImGui::Button(ICON_FA_ARROW_RIGHT, mCurrentPage == mLastPage)) {
+			SetPage(mCurrentPage + 1);
+		}
+
+		ImGui::SameLine();
+		if (ImGui::Button(ls->Edit.Get(), mSelectedEntry == -1)) {
+			ImGui::OpenPopup(ls->EditSaleEntryDialogTitle.Get());
+		}
+		if (ImGui::BeginPopupModal(ls->EditSaleEntryDialogTitle.Get(), &dummy, ImGuiWindowFlags_AlwaysAutoResize)) {
+			// TODO
+			ImGui::EndPopup();
+		}
+
+		if (ImGui::BeginTable("##SalesTable", 3)) {
+
+			ImGui::TableSetupColumn(ls->DatabaseCustomerColumn.Get());
+			ImGui::TableSetupColumn(ls->DatabaseDeadlineColumn.Get());
+			ImGui::TableSetupColumn(ls->DatabaseDeliveryTimeColumn.Get());
+			ImGui::TableHeadersRow();
+
+			for (int i : mCurrentPageEntries) {
+				auto& entry = mEntries[i];
+
+				ImGui::TableNextColumn();
+				if (ImGui::Selectable(entry.Customer.c_str(), mSelectedEntry == i)) {
+					mSelectedEntry = i;
+				}
+
+				ImGui::NextColumn();
+				ImGui::Text("%s", entry.Deadline.c_str());
+
+				ImGui::NextColumn();
+				if (entry.DeliveryTime.empty()) {
+					ImGui::Text("%s", ls->NotDeliveredMessage.Get());
+				} else {
+					ImGui::Text("%s", entry.DeliveryTime.c_str());
+				}
+			}
+
+			ImGui::EndTable();
+		}
+	}
+
+private:
+	void SetPage(int page) {
+		if (mCurrentPage != page) return;
+
+		mCurrentPage = page;
+		EnsureCacheCoversPage(page);
+
+		auto [begin, end] = CalcRangeForPage(page);
+		begin -= mFirstCachedRowId;
+		end -= mFirstCachedRowId;
+
+		mCurrentPageEntries.clear();
+		for (auto i = begin; i < end; ++i) {
+			if (mActiveEntries[i]) {
+				mCurrentPageEntries.push_back(i);
+			}
+		}
+	}
+
+	void EnsureCacheCoversPage(int page) {
+		auto [begin, end] = CalcRangeForPage(page);
+		EnsureCacheCovers(begin, end - 1);
+	}
+
+	void EnsureCacheCovers(int64_t firstRow, int64_t lastRow) {
+		if (firstRow > lastRow) {
+			std::swap(firstRow, lastRow);
+		}
+
+		int newFirst = mFirstCachedRowId;
+		int newLast = mLastCachedRowId;
+
+		bool doRebuild = false;
+		if (firstRow < mFirstCachedRowId) {
+			newFirst = CalcPageForRowId(firstRow) * kMaxEntriesPerPage;
+			doRebuild = true;
+		}
+		if (lastRow > mLastCachedRowId) {
+			newLast = CalcPageForRowId(lastRow) * kMaxEntriesPerPage;
+			doRebuild = true;
+		}
+		if (!doRebuild) return;
+
+		auto front = LoadRange(newFirst, mFirstCachedRowId);
+		auto back = LoadRange(mLastCachedRowId + 1, newLast + 1);
+
+		mEntries.insert(mEntries.begin(), front.begin(), front.end());
+		mEntries.insert(mEntries.end(), back.begin(), back.end());
+		// TODO update mActiveEntries
+
+		mFirstCachedRowId = newFirst;
+		mLastCachedRowId = newLast;
+	}
+
+	std::vector<SaleEntry> LoadRange(int64_t begin, int64_t end) {
+		std::vector<SaleEntry> result;
+
+		size_t size = end - begin;
+		if (size == 0) {
+			return result;
+		}
+
+		result.reserve(size);
+
+		auto& stmt = mProject->GetDatabase().GetSales().GetRowsStatement;
+		DEFER {
+			stmt.reset();
+		};
+
+		stmt.bind(1, begin);
+		stmt.bind(2, end);
+
+		while (true) {
+			bool hasResult = stmt.executeStep();
+			if (hasResult) {
+				result.push_back(stmt.getColumns<SaleEntry, 3>());
+			} else {
+				return result;
+			}
+		}
+	}
+
+	static int CalcPageForRowId(int64_t rowId) {
+		return rowId / kMaxEntriesPerPage;
+	}
+
+	/// Calculate range [begin, end) of row ids that the path-th page would show.
+	static std::pair<int64_t, int64_t> CalcRangeForPage(int page) {
+		int begin = page * kMaxEntriesPerPage;
+		return { begin, begin + kMaxEntriesPerPage };
+	}
+};
+
+class PurchaseEntry {
+public:
+	std::string Factory;
+	std::string OrderTime;
+	std::string DeliveryTime;
+};
+
+class PurchasesViewTab {
+private:
+	std::vector<PurchaseEntry> mEntries;
+	int mCurrentPage = 0;
+
+public:
+	void OnProjectChanged(Project* newProject) {
+		// TODO
+	}
+
+	void Draw() {
+		auto ls = LocaleStrings::Instance.get();
+		if (ImGui::BeginTable("##PurcahsesTable", 4)) {
+			ImGui::EndTable();
+		}
+	}
+};
+} // namespace
 
 void UI::DatabaseViewTab() {
-	// TODO
+	auto ls = LocaleStrings::Instance.get();
+	auto& uis = UIState::GetInstance();
+
+	static Project* currentProject = nullptr;
+	static auto salesView = std::make_unique<SalesViewTab>();
+	static auto purchasesView = std::make_unique<PurchasesViewTab>();
+
+	if (currentProject != uis.CurrentProject.get()) {
+		currentProject = uis.CurrentProject.get();
+		salesView->OnProjectChanged(currentProject);
+		purchasesView->OnProjectChanged(currentProject);
+	}
+
+	if (ImGui::BeginTabBar("##DatabaseViewTabs")) {
+		if (ImGui::BeginTabItem(ls->SalesViewTab.Get())) {
+			salesView->Draw();
+			ImGui::EndTabItem();
+		}
+		if (ImGui::BeginTabItem(ls->PurchasesViewTab.Get())) {
+			purchasesView->Draw();
+			ImGui::EndTabItem();
+		}
+		//		if (ImGui::BeginTabItem(ls->DeliveriesTableTab.Get())) {
+		//			ImGui::EndTabItem();
+		//		}
+	}
 }
diff --git a/core/src/UI/UI_Items.cpp b/core/src/UI/UI_Items.cpp
index 970d0df..a094f76 100644
--- a/core/src/UI/UI_Items.cpp
+++ b/core/src/UI/UI_Items.cpp
@@ -91,6 +91,8 @@ template <class T>
 void ItemListEntries(ItemList<T>& list, int& selectedIdx) {
 	constexpr bool kHasDescription = requires(T t) { t.GetDescription(); };
 	constexpr bool kHasEmail = requires(T t) { t.GetEmail(); };
+	constexpr bool kHasStock = requires(T t) { t.GetPrice(); };
+	constexpr bool kHasPrice = requires(T t) { t.GetPrice(); };
 	constexpr int kColumns = 1 /* Name column */ + kHasDescription + kHasEmail;
 
 	auto ls = LocaleStrings::Instance.get();
@@ -101,6 +103,8 @@ void ItemListEntries(ItemList<T>& list, int& selectedIdx) {
 		ImGui::TableSetupColumn(ls->ItemNameColumn.Get());
 		if constexpr (kHasDescription) ImGui::TableSetupColumn(ls->ItemDescriptionColumn.Get());
 		if constexpr (kHasEmail) ImGui::TableSetupColumn(ls->ItemEmailColumn.Get());
+		if constexpr (kHasStock) ImGui::TableSetupColumn(ls->ItemStockColumn.Get());
+		if constexpr (kHasPrice) ImGui::TableSetupColumn(ls->ItemPriceColumn.Get());
 		ImGui::TableHeadersRow();
 
 		size_t idx = 0;
@@ -111,24 +115,32 @@ void ItemListEntries(ItemList<T>& list, int& selectedIdx) {
 
 			ImGui::TableNextRow();
 
-			// Field: name
 			ImGui::TableNextColumn();
 			if (ImGui::Selectable(entry.GetName().c_str(), selectedIdx == idx, ImGuiSelectableFlags_SpanAllColumns)) {
 				selectedIdx = idx;
 			}
 
-			// Field: description
 			if constexpr (kHasDescription) {
 				ImGui::TableNextColumn();
 				ImGui::Text("%s", entry.GetDescription().c_str());
 			}
 
-			// Field: email
 			if constexpr (kHasEmail) {
 				ImGui::TableNextColumn();
 				ImGui::Text("%s", entry.GetEmail().c_str());
 			}
 
+			if constexpr (kHasStock) {
+				ImGui::TableNextColumn();
+				ImGui::Text("%d", entry.GetStock());
+			}
+
+			if constexpr (kHasPrice) {
+				ImGui::TableNextColumn();
+				// TODO format in dollars
+				ImGui::Text("%d", entry.GetPrice());
+			}
+
 			idx++;
 		}
 		ImGui::EndTable();
@@ -143,7 +155,7 @@ void ItemListEditor(ItemList<T>& list) {
 	static int selectedIdx = -1;
 	static T* editingItem = nullptr;
 
-	if (ImGui::Button(ls->AddItem.Get())) {
+	if (ImGui::Button(ls->Add.Get())) {
 		ImGui::SetNextWindowCentered();
 		ImGui::OpenPopup(ls->AddItemDialogTitle.Get());
 
@@ -165,7 +177,7 @@ void ItemListEditor(ItemList<T>& list) {
 	}
 
 	ImGui::SameLine();
-	if (ImGui::Button(ls->EditItem.Get(), selectedIdx == -1)) {
+	if (ImGui::Button(ls->Edit.Get(), selectedIdx == -1)) {
 		ImGui::SetNextWindowCentered();
 		ImGui::OpenPopup(ls->EditItemDialogTitle.Get());
 
@@ -179,7 +191,7 @@ void ItemListEditor(ItemList<T>& list) {
 	}
 
 	ImGui::SameLine();
-	if (ImGui::Button(ls->DeleteItem.Get(), selectedIdx == -1)) {
+	if (ImGui::Button(ls->Delete.Get(), selectedIdx == -1)) {
 		ImGui::SetNextWindowCentered();
 		ImGui::OpenPopup(ls->DeleteItemDialogTitle.Get());
 
diff --git a/core/src/UI/UI_MainWindow.cpp b/core/src/UI/UI_MainWindow.cpp
index a47efab..30505d6 100644
--- a/core/src/UI/UI_MainWindow.cpp
+++ b/core/src/UI/UI_MainWindow.cpp
@@ -195,12 +195,12 @@ void UI::MainWindow() {
 	ImGui::SetNextWindowPos({ 0, 0 });
 	ImGui::Begin("##MainWindow", nullptr, ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoResize);
 	if (ImGui::BeginTabBar("##MainWindowTabs")) {
-		if (ImGui::BeginTabItem(ls->TabSettings.Get())) {
+		if (ImGui::BeginTabItem(ls->SettingsTab.Get())) {
 			UI::SettingsTab();
 			ImGui::EndTabItem();
 		}
 
-		if (ImGui::BeginTabItem(ls->TabProject.Get(), nullptr)) {
+		if (ImGui::BeginTabItem(ls->ProjectTab.Get(), nullptr)) {
 			if (uis.CurrentProject) {
 				ProjectTab_Normal();
 			} else {
@@ -213,21 +213,16 @@ void UI::MainWindow() {
 			goto endTab;
 		}
 
-		if (ImGui::BeginTabItem(ls->TabDatabaseView.Get())) {
+		if (ImGui::BeginTabItem(ls->DatabaseViewTab.Get())) {
 			UI::DatabaseViewTab();
 			ImGui::EndTabItem();
 		}
 
-		if (ImGui::BeginTabItem(ls->TabItems.Get())) {
+		if (ImGui::BeginTabItem(ls->ItemsTab.Get())) {
 			UI::ItemsTab();
 			ImGui::EndTabItem();
 		}
 
-		if (ImGui::BeginTabItem(ls->TabExport.Get())) {
-			UI::ExportTab();
-			ImGui::EndTabItem();
-		}
-
 	endTab:
 		ImGui::EndTabBar();
 	}
diff --git a/core/src/Utils/Macros.hpp b/core/src/Utils/Macros.hpp
new file mode 100644
index 0000000..cb949b2
--- /dev/null
+++ b/core/src/Utils/Macros.hpp
@@ -0,0 +1,6 @@
+#pragma  once
+
+#define CONCAT_IMPL(a, b) a##b
+#define CONCAT(a, b) CONCAT_IMPL(a, b)
+
+#define UNIQUE_NAME(prefix) CONCAT(prefix, __LINE__)
diff --git a/core/src/Utils/ScopeGuard.hpp b/core/src/Utils/ScopeGuard.hpp
new file mode 100644
index 0000000..ed8d4ea
--- /dev/null
+++ b/core/src/Utils/ScopeGuard.hpp
@@ -0,0 +1,35 @@
+#pragma once
+
+#include "Utils/Macros.hpp"
+
+#include <utility>
+
+template <class TCleanupFunc>
+class ScopeGuard {
+private:
+	TCleanupFunc mFunc;
+	bool mDismissed = false;
+
+public:
+	/// Specifically left this implicit so that constructs like
+	/// \code
+	/// ScopeGuard sg = [&]() { res.Cleanup(); };
+	/// \endcode
+	/// would work. It is highly discourage and unlikely that one would want to use ScopeGuard as a function
+	/// parameter, so the normal argument that implicit conversion are harmful doesn't really apply here.
+	ScopeGuard(TCleanupFunc func)
+		: mFunc{ std::move(func) } {
+	}
+
+	~ScopeGuard() {
+		if (!mDismissed) {
+			mFunc();
+		}
+	}
+
+	void Dismiss() noexcept {
+		mDismissed = true;
+	}
+};
+
+#define DEFER ScopeGuard UNIQUE_NAME(scopeGuard) = [&]()