diff --git a/.gitignore b/.gitignore
index d9273a9..890199e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@ target/
 !.mvn/wrapper/maven-wrapper.jar
 !**/src/main/**/target/
 !**/src/test/**/target/
+/src/main/resources/application.properties
 
 ### STS ###
 .apt_generated
diff --git a/pom.xml b/pom.xml
index e90d662..02f1b6f 100644
--- a/pom.xml
+++ b/pom.xml
@@ -6,7 +6,7 @@
         <groupId>org.springframework.boot</groupId>
         <artifactId>spring-boot-starter-parent</artifactId>
         <version>3.1.3</version>
-        <relativePath/> <!-- lookup parent from repository -->
+        <relativePath/>
     </parent>
     <groupId>com.faf223</groupId>
     <artifactId>ExpenseTrackerFAF</artifactId>
@@ -20,37 +20,31 @@
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-web</artifactId>
+            <version>3.1.4</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-data-jpa</artifactId>
         </dependency>
+
         <dependency>
-            <groupId>com.microsoft.sqlserver</groupId>
-            <artifactId>mssql-jdbc</artifactId>
+            <groupId>org.mariadb.jdbc</groupId>
+            <artifactId>mariadb-java-client</artifactId>
+            <version>3.2.0</version>
         </dependency>
 
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-test</artifactId>
             <scope>test</scope>
-            <version>3.1.2</version>
         </dependency>
         <dependency>
             <groupId>org.springframework.boot</groupId>
             <artifactId>spring-boot-starter-security</artifactId>
-        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-data-jpa -->
         </dependency>
         <dependency>
-            <groupId>org.springframework.boot</groupId>
-            <artifactId>spring-boot-starter-data-jpa</artifactId>
-            <version>3.1.3</version>
-        </dependency>
-        <!-- https://mvnrepository.com/artifact/com.mysql/mysql-connector-j -->
-        <dependency>
-            <groupId>com.mysql</groupId>
-            <artifactId>mysql-connector-j</artifactId>
-            <version>8.1.0</version>
+            <groupId>org.projectlombok</groupId>
+            <artifactId>lombok</artifactId>
         </dependency>
         <dependency>
             <groupId>io.jsonwebtoken</groupId>
@@ -82,5 +76,4 @@
             </plugin>
         </plugins>
     </build>
-
 </project>
diff --git a/src/main/java/com/faf223/expensetrackerfaf/controller/BasicController.java b/src/main/java/com/faf223/expensetrackerfaf/controller/BasicController.java
deleted file mode 100644
index fbb3f0c..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/controller/BasicController.java
+++ /dev/null
@@ -1,26 +0,0 @@
-package com.faf223.expensetrackerfaf.controller;
-
-import com.faf223.expensetrackerfaf.model.BasicEntity;
-import com.faf223.expensetrackerfaf.repository.BasicRepository;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.RequestMapping;
-import org.springframework.web.bind.annotation.RestController;
-
-import java.util.List;
-
-@RestController
-@RequestMapping("/api/getData")
-public class BasicController {
-    private final BasicRepository basicRepository;
-
-    @Autowired
-    public BasicController(BasicRepository basicRepository) {
-        this.basicRepository = basicRepository;
-    }
-
-    @GetMapping()
-    public List<BasicEntity> listDepartments() {
-        return basicRepository.findAll();
-    }
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/controller/ExpenseController.java b/src/main/java/com/faf223/expensetrackerfaf/controller/ExpenseController.java
new file mode 100644
index 0000000..9769c9a
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/controller/ExpenseController.java
@@ -0,0 +1,31 @@
+package com.faf223.expensetrackerfaf.controller;
+
+import com.faf223.expensetrackerfaf.model.Expense;
+import com.faf223.expensetrackerfaf.service.ExpenseService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/expenses")
+public class ExpenseController {
+
+    @Autowired
+    private ExpenseService expenseService;
+
+    @GetMapping("/user/{userUuid}")
+    public ResponseEntity<List<Expense>> getExpensesByUser(@PathVariable String userUuid) {
+        List<Expense> expenses = expenseService.getExpensesByUserId(userUuid);
+        if (!expenses.isEmpty()) {
+            return ResponseEntity.ok(expenses);
+        } else {
+            return ResponseEntity.notFound().build();
+        }
+    }
+}
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/controller/IncomeController.java b/src/main/java/com/faf223/expensetrackerfaf/controller/IncomeController.java
new file mode 100644
index 0000000..078c65a
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/controller/IncomeController.java
@@ -0,0 +1,30 @@
+package com.faf223.expensetrackerfaf.controller;
+
+import com.faf223.expensetrackerfaf.model.Income;
+import com.faf223.expensetrackerfaf.service.IncomeService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.List;
+
+@RestController
+@RequestMapping("/incomes")
+public class IncomeController {
+    @Autowired
+    private IncomeService incomeService;
+
+    @GetMapping("/user/{userUuid}")
+    public ResponseEntity<List<Income>> getIncomesByUser(@PathVariable String userUuid) {
+        List<Income> incomes = incomeService.getIncomesByUserId(userUuid);
+        if (!incomes.isEmpty()) {
+            return ResponseEntity.ok(incomes);
+        } else {
+            return ResponseEntity.notFound().build();
+        }
+    }
+}
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/controller/MainController.java b/src/main/java/com/faf223/expensetrackerfaf/controller/MainController.java
index 20112c1..47ba33b 100644
--- a/src/main/java/com/faf223/expensetrackerfaf/controller/MainController.java
+++ b/src/main/java/com/faf223/expensetrackerfaf/controller/MainController.java
@@ -1,66 +1,66 @@
-package com.faf223.expensetrackerfaf.controller;
-
-import com.faf223.expensetrackerfaf.model.Expense;
-import com.faf223.expensetrackerfaf.model.Income;
-import com.faf223.expensetrackerfaf.model.Role;
-import com.faf223.expensetrackerfaf.model.User;
-import org.springframework.web.bind.annotation.*;
-
-import java.util.List;
-
-@RestController
-public class MainController {
-
-    @GetMapping("/")
-    public String helloWorld() {
-        return "Hello, World!";
-    }
-
-    @GetMapping("/users/get/{id}")
-    public User getUser(@PathVariable int id) {
-        return new User(id, "Test", null, null, null, null, null);
-    }
-
-    @PostMapping("/users/set/{id}/name")
-    public String setName(@PathVariable int id,
-                          @RequestParam("name") String name) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/email")
-    public String setEmail(@PathVariable int id,
-                           @RequestParam("email") String email) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/login")
-    public String setLogin(@PathVariable int id,
-                           @RequestParam("login") String login) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/password")
-    public String setPassword(@PathVariable int id,
-                              @RequestParam("password") String password) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/role")
-    public String setRole(@PathVariable int id,
-                          @RequestParam("role") Role role) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/expenses")
-    public String setExpenses(@PathVariable int id,
-                              @RequestParam("expenses") List<Expense> expenses) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-    @PostMapping("/users/set/{id}/incomes")
-    public String setIncomes(@PathVariable int id,
-                             @RequestParam("incomes")List<Income> incomes) {
-        throw new UnsupportedOperationException("Waiting for the DB.");
-    }
-
-}
\ No newline at end of file
+//package com.faf223.expensetrackerfaf.controller;
+//
+//import com.faf223.expensetrackerfaf.model.Expense;
+//import com.faf223.expensetrackerfaf.model.Income;
+//import com.faf223.expensetrackerfaf.model.Role;
+//import com.faf223.expensetrackerfaf.model.User;
+//import org.springframework.web.bind.annotation.*;
+//
+//import java.util.List;
+//
+//@RestController
+//public class MainController {
+//
+//    @GetMapping("/")
+//    public String helloWorld() {
+//        return "Hello, World!";
+//    }
+//
+//    @GetMapping("/users/get/{id}")
+//    public User getUser(@PathVariable int id) {
+//        return new User(id, "Test", null, null, null, null, null, null);
+//    }
+//
+//    @PostMapping("/users/set/{id}/name")
+//    public String setName(@PathVariable int id,
+//                          @RequestParam("name") String name) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/email")
+//    public String setEmail(@PathVariable int id,
+//                           @RequestParam("email") String email) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/login")
+//    public String setLogin(@PathVariable int id,
+//                           @RequestParam("login") String login) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/password")
+//    public String setPassword(@PathVariable int id,
+//                              @RequestParam("password") String password) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/role")
+//    public String setRole(@PathVariable int id,
+//                          @RequestParam("role") Role role) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/expenses")
+//    public String setExpenses(@PathVariable int id,
+//                              @RequestParam("expenses") List<Expense> expenses) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//    @PostMapping("/users/set/{id}/incomes")
+//    public String setIncomes(@PathVariable int id,
+//                             @RequestParam("incomes")List<Income> incomes) {
+//        throw new UnsupportedOperationException("Waiting for the DB.");
+//    }
+//
+//}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/controller/UserController.java b/src/main/java/com/faf223/expensetrackerfaf/controller/UserController.java
new file mode 100644
index 0000000..a9de44e
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/controller/UserController.java
@@ -0,0 +1,29 @@
+package com.faf223.expensetrackerfaf.controller;
+
+import com.faf223.expensetrackerfaf.model.User;
+import com.faf223.expensetrackerfaf.service.UserService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+@RequestMapping("/users")
+public class UserController {
+
+    @Autowired
+    private UserService userService;
+
+    @GetMapping("/{userUuid}")
+    public ResponseEntity<User> getUser(@PathVariable String userUuid) {
+        User user = userService.getUserById(userUuid);
+        if (user != null) {
+            return ResponseEntity.ok(user);
+        } else {
+            return ResponseEntity.notFound().build();
+        }
+    }
+}
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/custom/UppercaseStrategy.java b/src/main/java/com/faf223/expensetrackerfaf/custom/UppercaseStrategy.java
deleted file mode 100644
index 9c3cc83..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/custom/UppercaseStrategy.java
+++ /dev/null
@@ -1,39 +0,0 @@
-package com.faf223.expensetrackerfaf.custom;
-
-import org.hibernate.boot.model.naming.Identifier;
-import org.hibernate.boot.model.naming.PhysicalNamingStrategy;
-import org.hibernate.engine.jdbc.env.spi.JdbcEnvironment;
-
-public class UppercaseStrategy implements PhysicalNamingStrategy {
-
-    @Override
-    public Identifier toPhysicalCatalogName(Identifier identifier, JdbcEnvironment jdbcEnvironment) {
-        return identifier; // No modification for catalog name
-    }
-
-    @Override
-    public Identifier toPhysicalSchemaName(Identifier identifier, JdbcEnvironment jdbcEnvironment) {
-        return identifier; // No modification for schema name
-    }
-
-    @Override
-    public Identifier toPhysicalTableName(Identifier name, JdbcEnvironment context) {
-        String tableName = name.getText();
-        return new Identifier(tableName, name.isQuoted());
-    }
-
-    @Override
-    public Identifier toPhysicalSequenceName(Identifier identifier, JdbcEnvironment jdbcEnvironment) {
-        return identifier; // No modification for sequence name
-    }
-
-    @Override
-    public Identifier toPhysicalColumnName(Identifier identifier, JdbcEnvironment jdbcEnvironment) {
-        return identifier; // No modification for column name
-    }
-
-    @Override
-    public Identifier toPhysicalTypeName(Identifier logicalName, JdbcEnvironment jdbcEnvironment) {
-        return PhysicalNamingStrategy.super.toPhysicalTypeName(logicalName, jdbcEnvironment);
-    }
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/BasicEntity.java b/src/main/java/com/faf223/expensetrackerfaf/model/BasicEntity.java
deleted file mode 100644
index 06f0644..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/model/BasicEntity.java
+++ /dev/null
@@ -1,37 +0,0 @@
-package com.faf223.expensetrackerfaf.model;
-
-import jakarta.persistence.*;
-import java.util.Date;
-
-@Entity
-@Table(name = "Department", schema = "HumanResources")
-public class BasicEntity {
-    @Id
-    @GeneratedValue(strategy = GenerationType.IDENTITY)
-    @Column(name = "DepartmentID")
-    private Short departmentId;
-
-    @Column(name = "GroupName", nullable = false, length = 50)
-    private String groupName;
-
-    @Column(name = "ModifiedDate", nullable = false)
-    @Temporal(TemporalType.TIMESTAMP)
-    private Date modifiedDate;
-
-    @Column(name = "Name", nullable = false, length = 50)
-    private String name;
-
-    public Short getDepartmentId() {
-        return departmentId;
-    }
-    public String getGroupName() {
-        return groupName;
-    }
-    public Date getModifiedDate() {
-        return modifiedDate;
-    }
-
-    public String getName() {
-        return name;
-    }
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/Categories.java b/src/main/java/com/faf223/expensetrackerfaf/model/Categories.java
deleted file mode 100644
index a309f85..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/model/Categories.java
+++ /dev/null
@@ -1,34 +0,0 @@
-
-package com.faf223.expensetrackerfaf.model;
-
-public class Categories {
-
-    public enum ExpenseCategory {
-        CREDIT, BUY, BUSINESS, ENTERTAINMENT, RESTAURANTS_AND_CAFE, COMMUNAL_PAYMENTS, SUPERMARKET, MISC;
-
-        public String getEffectiveName() {
-            return Categories.getEffectiveName(this.name());
-        }
-    }
-
-    public enum IncomeCategory {
-        P2P, SALARY, GIFT, CREDIT, MISC;
-
-        public String getEffectiveName() {
-            return Categories.getEffectiveName(this.name());
-        }
-    }
-
-    private static String getEffectiveName(String name) {
-        String[] arr = name.split("_");
-        StringBuilder result = new StringBuilder();
-        for(String entry : arr) {
-            String[] entryArr = entry.split("");
-            StringBuilder builder = new StringBuilder(entryArr[0]);
-            for(int i = 1; i < entry.length(); i++) builder.append(entryArr[i].toLowerCase());
-            result.append(builder).append(" ");
-        }
-        return result.toString();
-    }
-
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/Credential.java b/src/main/java/com/faf223/expensetrackerfaf/model/Credential.java
new file mode 100644
index 0000000..aa2b4bd
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/model/Credential.java
@@ -0,0 +1,20 @@
+package com.faf223.expensetrackerfaf.model;
+
+import jakarta.persistence.*;
+import lombok.Data;
+
+@Data
+@Entity(name = "credentials")
+public class Credential {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long credentialId;
+
+    @ManyToOne
+    @JoinColumn(name = "user_uuid")
+    private User user;
+
+    private String email;
+    private String password;
+}
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/Expense.java b/src/main/java/com/faf223/expensetrackerfaf/model/Expense.java
index 5c43723..67df9cf 100644
--- a/src/main/java/com/faf223/expensetrackerfaf/model/Expense.java
+++ b/src/main/java/com/faf223/expensetrackerfaf/model/Expense.java
@@ -1,63 +1,26 @@
-
 package com.faf223.expensetrackerfaf.model;
-import com.faf223.expensetrackerfaf.util.IMoneyTransaction;
 import jakarta.persistence.*;
+import lombok.Data;
 
-@Entity
-@Table(name = "expense")
-public class Expense implements IMoneyTransaction {
+import java.math.BigDecimal;
+import java.time.LocalDate;
 
+@Data
+@Entity(name = "expenses")
+public class Expense {
     @Id
-    @Column(name = "id")
     @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private long id;
+    private Long expenseId;
 
     @ManyToOne
-    @JoinColumn(name = "user_id", referencedColumnName = "id")
+    @JoinColumn(name = "user_uuid")
     private User user;
-    private int amount;
-    private Categories.ExpenseCategory category;
 
-    public Expense(User user, int amount, Categories.ExpenseCategory category) {
-        this.user = user;
-        this.amount = amount;
-        this.category = category;
-    }
+    @ManyToOne
+    @JoinColumn(name = "category_id")
+    private ExpenseCategory category;
 
-    public Expense() {}
-
-    public long getId() {
-        return id;
-    }
-
-    public void setId(long id) {
-        this.id = id;
-    }
-
-    @Override
-    public User getUser() {
-        return user;
-    }
-
-    public void setUser(User user) {
-        this.user = user;
-    }
-
-    @Override
-    public int getAmount() {
-        return amount;
-    }
-
-    public void setAmount(int amount) {
-        this.amount = amount;
-    }
-
-    @Override
-    public String getCategory() {
-        return category.getEffectiveName();
-    }
-
-    public void setCategory(Categories.ExpenseCategory category) {
-        this.category = category;
-    }
+    private LocalDate date;
+    private BigDecimal amount;
 }
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/ExpenseCategory.java b/src/main/java/com/faf223/expensetrackerfaf/model/ExpenseCategory.java
new file mode 100644
index 0000000..7662ce6
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/model/ExpenseCategory.java
@@ -0,0 +1,17 @@
+package com.faf223.expensetrackerfaf.model;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import lombok.Data;
+
+@Data
+@Entity(name = "expense_categories")
+public class ExpenseCategory {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long categoryId;
+
+    private String categoryName;
+}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/Income.java b/src/main/java/com/faf223/expensetrackerfaf/model/Income.java
index 57a2ea6..38344a7 100644
--- a/src/main/java/com/faf223/expensetrackerfaf/model/Income.java
+++ b/src/main/java/com/faf223/expensetrackerfaf/model/Income.java
@@ -1,63 +1,26 @@
 package com.faf223.expensetrackerfaf.model;
 
-import com.faf223.expensetrackerfaf.util.IMoneyTransaction;
 import jakarta.persistence.*;
+import lombok.Data;
 
-@Entity
-@Table(name = "income")
-public class Income implements IMoneyTransaction {
+import java.math.BigDecimal;
+import java.time.LocalDate;
 
+@Data
+@Entity(name = "incomes")
+public class Income {
     @Id
-    @Column(name = "id")
     @GeneratedValue(strategy = GenerationType.IDENTITY)
-    private long id;
+    private Long incomeId;
 
     @ManyToOne
-    @JoinColumn(name = "user_id", referencedColumnName = "id")
+    @JoinColumn(name = "user_uuid")
     private User user;
-    private int amount;
-    private Categories.IncomeCategory category;
 
-    public Income(User user, int amount, Categories.IncomeCategory category) {
-        this.user = user;
-        this.amount = amount;
-        this.category = category;
-    }
+    @ManyToOne
+    @JoinColumn(name = "category_id")
+    private IncomeCategory category;
 
-    public Income() {}
-
-    public long getId() {
-        return id;
-    }
-
-    public void setId(long id) {
-        this.id = id;
-    }
-
-    public void setUser(User user) {
-        this.user = user;
-    }
-
-    @Override
-    public User getUser() {
-        return user;
-    }
-
-    @Override
-    public int getAmount() {
-        return amount;
-    }
-
-    @Override
-    public String getCategory() {
-        return category.getEffectiveName();
-    }
-
-    public void setAmount(int amount) {
-        this.amount = amount;
-    }
-
-    public void setCategory(Categories.IncomeCategory category) {
-        this.category = category;
-    }
+    private LocalDate date;
+    private BigDecimal amount;
 }
diff --git a/src/main/java/com/faf223/expensetrackerfaf/model/IncomeCategory.java b/src/main/java/com/faf223/expensetrackerfaf/model/IncomeCategory.java
new file mode 100644
index 0000000..8bb54f0
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/model/IncomeCategory.java
@@ -0,0 +1,18 @@
+package com.faf223.expensetrackerfaf.model;
+
+import jakarta.persistence.Entity;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import lombok.Data;
+
+@Data
+@Entity(name = "income_categories")
+public class IncomeCategory {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long categoryId;
+
+    private String categoryName;
+}
+
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/BasicRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/BasicRepository.java
deleted file mode 100644
index 94f10e3..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/repository/BasicRepository.java
+++ /dev/null
@@ -1,12 +0,0 @@
-package com.faf223.expensetrackerfaf.repository;
-
-import com.faf223.expensetrackerfaf.model.BasicEntity;
-
-import java.util.List;
-
-import org.springframework.data.jpa.repository.JpaRepository;
-
-public interface BasicRepository extends JpaRepository<BasicEntity, Short> {
-    // You can define custom query methods here if needed
-}
-
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/CredentialRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/CredentialRepository.java
new file mode 100644
index 0000000..346136a
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/repository/CredentialRepository.java
@@ -0,0 +1,9 @@
+package com.faf223.expensetrackerfaf.repository;
+
+import com.faf223.expensetrackerfaf.model.Credential;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface CredentialRepository extends JpaRepository<Credential, Long> {
+}
\ No newline at end of file
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseCategoryRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseCategoryRepository.java
new file mode 100644
index 0000000..91deb28
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseCategoryRepository.java
@@ -0,0 +1,9 @@
+package com.faf223.expensetrackerfaf.repository;
+
+import com.faf223.expensetrackerfaf.model.ExpenseCategory;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface ExpenseCategoryRepository extends JpaRepository<ExpenseCategory, Long> {
+}
\ No newline at end of file
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseRepository.java
index edc0209..4cd39d0 100644
--- a/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseRepository.java
+++ b/src/main/java/com/faf223/expensetrackerfaf/repository/ExpenseRepository.java
@@ -2,6 +2,11 @@ package com.faf223.expensetrackerfaf.repository;
 
 import com.faf223.expensetrackerfaf.model.Expense;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
 
+import java.util.List;
+
+@Repository
 public interface ExpenseRepository extends JpaRepository<Expense, Long> {
+    List<Expense> findByUserUserUuid(String userUuid);
 }
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeCategoryRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeCategoryRepository.java
new file mode 100644
index 0000000..e6c8402
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeCategoryRepository.java
@@ -0,0 +1,9 @@
+package com.faf223.expensetrackerfaf.repository;
+
+import com.faf223.expensetrackerfaf.model.IncomeCategory;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+@Repository
+public interface IncomeCategoryRepository extends JpaRepository<IncomeCategory, Long> {
+}
\ No newline at end of file
diff --git a/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeRepository.java b/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeRepository.java
index 818dcfd..9a1a592 100644
--- a/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeRepository.java
+++ b/src/main/java/com/faf223/expensetrackerfaf/repository/IncomeRepository.java
@@ -2,6 +2,11 @@ package com.faf223.expensetrackerfaf.repository;
 
 import com.faf223.expensetrackerfaf.model.Income;
 import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
 
+import java.util.List;
+
+@Repository
 public interface IncomeRepository extends JpaRepository<Income, Long> {
+    List<Income> findByUserUserUuid(String userUuid);
 }
diff --git a/src/main/java/com/faf223/expensetrackerfaf/service/BasicService.java b/src/main/java/com/faf223/expensetrackerfaf/service/BasicService.java
deleted file mode 100644
index a424dce..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/service/BasicService.java
+++ /dev/null
@@ -1,9 +0,0 @@
-package com.faf223.expensetrackerfaf.service;
-
-import com.faf223.expensetrackerfaf.model.BasicEntity;
-
-import java.util.List;
-
-public interface BasicService {
-    List<BasicEntity> getAllData();
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/service/BasicServiceImpl.java b/src/main/java/com/faf223/expensetrackerfaf/service/BasicServiceImpl.java
deleted file mode 100644
index 8a83825..0000000
--- a/src/main/java/com/faf223/expensetrackerfaf/service/BasicServiceImpl.java
+++ /dev/null
@@ -1,23 +0,0 @@
-package com.faf223.expensetrackerfaf.service;
-
-import com.faf223.expensetrackerfaf.model.BasicEntity;
-import com.faf223.expensetrackerfaf.repository.BasicRepository;
-import org.springframework.beans.factory.annotation.Autowired;
-import org.springframework.stereotype.Service;
-
-import java.util.List;
-
-@Service
-public class BasicServiceImpl implements BasicService {
-    private final BasicRepository basicRepository;
-
-    @Autowired
-    public BasicServiceImpl(BasicRepository basicRepository) {
-        this.basicRepository = basicRepository;
-    }
-
-    @Override
-    public List<BasicEntity> getAllData() {
-        return basicRepository.findAll();
-    }
-}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/service/ExpenseService.java b/src/main/java/com/faf223/expensetrackerfaf/service/ExpenseService.java
new file mode 100644
index 0000000..443ca0d
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/service/ExpenseService.java
@@ -0,0 +1,19 @@
+package com.faf223.expensetrackerfaf.service;
+
+import com.faf223.expensetrackerfaf.model.Expense;
+import com.faf223.expensetrackerfaf.repository.ExpenseRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class ExpenseService {
+
+    @Autowired
+    private ExpenseRepository expenseRepository;
+
+    public List<Expense> getExpensesByUserId(String userUuid) {
+        return expenseRepository.findByUserUserUuid(userUuid);
+    }
+}
\ No newline at end of file
diff --git a/src/main/java/com/faf223/expensetrackerfaf/service/IncomeService.java b/src/main/java/com/faf223/expensetrackerfaf/service/IncomeService.java
new file mode 100644
index 0000000..5ca97d1
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/service/IncomeService.java
@@ -0,0 +1,18 @@
+package com.faf223.expensetrackerfaf.service;
+
+import com.faf223.expensetrackerfaf.model.Income;
+import com.faf223.expensetrackerfaf.repository.IncomeRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+import java.util.List;
+
+@Service
+public class IncomeService {
+    @Autowired
+    private IncomeRepository incomeRepository;
+
+    public List<Income> getIncomesByUserId(String userUuid) {
+        return incomeRepository.findByUserUserUuid(userUuid);
+    }
+}
diff --git a/src/main/java/com/faf223/expensetrackerfaf/service/UserService.java b/src/main/java/com/faf223/expensetrackerfaf/service/UserService.java
new file mode 100644
index 0000000..e9c3798
--- /dev/null
+++ b/src/main/java/com/faf223/expensetrackerfaf/service/UserService.java
@@ -0,0 +1,17 @@
+package com.faf223.expensetrackerfaf.service;
+
+import com.faf223.expensetrackerfaf.model.User;
+import com.faf223.expensetrackerfaf.repository.UserRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.stereotype.Service;
+
+@Service
+public class UserService {
+
+    @Autowired
+    private UserRepository userRepository;
+
+    public User getUserById(String userUuid) {
+        return userRepository.findById(userUuid).orElse(null);
+    }
+}
\ No newline at end of file