diff --git a/tests/test_database.py b/tests/test_database.py
new file mode 100644
index 0000000..e23ba18
--- /dev/null
+++ b/tests/test_database.py
@@ -0,0 +1,137 @@
+"""Tests for database operations."""
+
+import pytest
+import tempfile
+import os
+import sys
+sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
+
+from shell_memory.database import Database
+from shell_memory.models import Command, Pattern, Session, ScriptTemplate
+
+
+@pytest.fixture
+def temp_db():
+    with tempfile.NamedTemporaryFile(suffix=".db", delete=False) as f:
+        db_path = f.name
+    db = Database(db_path)
+    yield db
+    os.unlink(db_path)
+
+
+class TestDatabaseCommandOperations:
+    def test_add_command(self, temp_db):
+        cmd = Command(
+            command="ls -la",
+            description="List files",
+            tags=["filesystem", "list"],
+        )
+        cmd_id = temp_db.add_command(cmd)
+        assert cmd_id is not None
+
+    def test_get_command(self, temp_db):
+        cmd = Command(command="pwd", description="Print directory")
+        cmd_id = temp_db.add_command(cmd)
+        retrieved = temp_db.get_command(cmd_id)
+        assert retrieved is not None
+        assert retrieved.command == "pwd"
+
+    def test_get_all_commands(self, temp_db):
+        temp_db.add_command(Command(command="cmd1"))
+        temp_db.add_command(Command(command="cmd2"))
+        commands = temp_db.get_all_commands()
+        assert len(commands) == 2
+
+    def test_search_commands(self, temp_db):
+        temp_db.add_command(Command(command="git status", description="Check repo"))
+        temp_db.add_command(Command(command="git diff", description="Show changes"))
+        results = temp_db.search_commands("git")
+        assert len(results) >= 2
+
+    def test_delete_command(self, temp_db):
+        cmd = Command(command="to_delete")
+        cmd_id = temp_db.add_command(cmd)
+        result = temp_db.delete_command(cmd_id)
+        assert result is True
+        retrieved = temp_db.get_command(cmd_id)
+        assert retrieved is None
+
+    def test_update_command_usage(self, temp_db):
+        cmd = Command(command="frequent_cmd")
+        cmd_id = temp_db.add_command(cmd)
+        temp_db.update_command_usage(cmd_id)
+        temp_db.update_command_usage(cmd_id)
+        retrieved = temp_db.get_command(cmd_id)
+        assert retrieved.usage_count == 2
+
+
+class TestDatabasePatternOperations:
+    def test_add_pattern(self, temp_db):
+        pattern = Pattern(
+            name="Git workflow",
+            command_ids=[1, 2, 3],
+            frequency=5,
+        )
+        pattern_id = temp_db.add_pattern(pattern)
+        assert pattern_id is not None
+
+    def test_get_patterns(self, temp_db):
+        temp_db.add_pattern(Pattern(command_ids=[1, 2], frequency=3))
+        temp_db.add_pattern(Pattern(command_ids=[3, 4], frequency=1))
+        patterns = temp_db.get_patterns(min_frequency=2)
+        assert len(patterns) == 1
+
+    def test_update_pattern_frequency(self, temp_db):
+        pattern = Pattern(command_ids=[1, 2], frequency=1)
+        pattern_id = temp_db.add_pattern(pattern)
+        temp_db.update_pattern_frequency(pattern_id)
+        patterns = temp_db.get_patterns(min_frequency=1)
+        assert patterns[0].frequency == 2
+
+
+class TestDatabaseSessionOperations:
+    def test_add_session(self, temp_db):
+        session = Session(
+            name="Test session",
+            commands=[{"command": "ls"}, {"command": "pwd"}],
+        )
+        session_id = temp_db.add_session(session)
+        assert session_id is not None
+
+    def test_get_sessions(self, temp_db):
+        temp_db.add_session(Session(name="session1"))
+        temp_db.add_session(Session(name="session2"))
+        sessions = temp_db.get_sessions()
+        assert len(sessions) == 2
+
+    def test_get_session(self, temp_db):
+        session = Session(name="my session")
+        session_id = temp_db.add_session(session)
+        retrieved = temp_db.get_session(session_id)
+        assert retrieved is not None
+        assert retrieved.name == "my session"
+
+
+class TestDatabaseScriptTemplateOperations:
+    def test_add_script_template(self, temp_db):
+        template = ScriptTemplate(
+            keywords=["deploy", "app"],
+            template="#!/bin/bash\necho deploy",
+            description="Deploy app",
+        )
+        template_id = temp_db.add_script_template(template)
+        assert template_id is not None
+
+    def test_get_script_templates(self, temp_db):
+        temp_db.add_script_template(ScriptTemplate(keywords=["test"], template="pytest"))
+        templates = temp_db.get_script_templates()
+        assert len(templates) >= 1
+
+    def test_search_script_templates(self, temp_db):
+        temp_db.add_script_template(ScriptTemplate(
+            keywords=["docker", "build"],
+            template="docker build",
+            description="Build Docker image",
+        ))
+        results = temp_db.search_script_templates("docker")
+        assert len(results) >= 1
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