diff --git a/reverse_engineering/databaseService/databaseService.js b/reverse_engineering/databaseService/databaseService.js
index 140435b..b7bba22 100644
--- a/reverse_engineering/databaseService/databaseService.js
+++ b/reverse_engineering/databaseService/databaseService.js
@@ -5,6 +5,7 @@ const { getObjectsFromDatabase, getNewConnectionClientByDb } = require('./helper
 const msal = require('@azure/msal-node');
 const getSampleDocSize = require('../helpers/getSampleDocSize');
 const { logAuthTokenInfo } = require('../helpers/logInfo');
+const { getConnection } = require('./helpers/connection');
 
 const QUERY_REQUEST_TIMEOUT = 60000;
 
@@ -17,12 +18,6 @@ const getConnectionClient = async (connectionInfo, logger) => {
 	const tenantId = connectionInfo.connectionTenantId || connectionInfo.tenantId || 'common';
 	const queryRequestTimeout = Number(connectionInfo.queryRequestTimeout) || QUERY_REQUEST_TIMEOUT;
 
-	logger.log(
-		'info',
-		`hostname: ${hostName}, username: ${userName}, auth method: ${connectionInfo.authMethod}`,
-		'Auth info',
-	);
-
 	const commonConfig = {
 		server: connectionInfo.host,
 		port: +connectionInfo.port,
@@ -38,63 +33,20 @@ const getConnectionClient = async (connectionInfo, logger) => {
 	const clientId = '0dc36597-bc44-49f8-a4a7-ae5401959b85';
 	const redirectUri = 'http://localhost:8080';
 
-	switch (connectionInfo.authMethod) {
-		case 'Username / Password':
-			return sql.connect({
-				...commonConfig,
-				...credentialsConfig,
-				options: {
-					encrypt: true,
-					enableArithAbort: true,
-				},
-			});
-		case 'Username / Password (Windows)':
-			return sql.connect({
-				...commonConfig,
-				...credentialsConfig,
-				domain: connectionInfo.userDomain,
-				options: {
-					encrypt: false,
-					enableArithAbort: true,
-				},
-			});
-		case 'Azure Active Directory (MFA)':
-			const token = await getToken({ connectionInfo, tenantId, clientId, redirectUri, logger });
-			logAuthTokenInfo({ token, logger });
-			return sql.connect({
-				...commonConfig,
-				options: {
-					encrypt: true,
-					enableArithAbort: true,
-				},
-				authentication: {
-					type: 'azure-active-directory-access-token',
-					options: {
-						token,
-					},
-				},
-			});
-		case 'Azure Active Directory (Username / Password)':
-			return sql.connect({
-				...commonConfig,
-				...credentialsConfig,
-				options: {
-					encrypt: true,
-					enableArithAbort: true,
-				},
-				authentication: {
-					type: 'azure-active-directory-password',
-					options: {
-						userName: connectionInfo.userName,
-						password: connectionInfo.userPassword,
-						tenantId,
-						clientId,
-					},
-				},
-			});
-	}
+	const connection = getConnection({
+		type: connectionInfo.authMethod,
+		data: {
+			connectionInfo,
+			commonConfig,
+			credentialsConfig,
+			tenantId,
+			clientId,
+			redirectUri,
+			logger,
+		},
+	});
 
-	return await sql.connect(connectionInfo.connectionString);
+	return connection.connect();
 };
 
 const isEmail = name => /^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(name || '');
@@ -513,98 +465,13 @@ const mapResponse = async (response = {}) => {
 	return (await response).recordset;
 };
 
-const getTokenByMSAL = async ({ connectionInfo, redirectUri, clientId, tenantId, logger }) => {
-	try {
-		const pca = new msal.PublicClientApplication(getAuthConfig(clientId, tenantId, logger.log));
-		const tokenRequest = {
-			code: connectionInfo?.externalBrowserQuery?.code || '',
-			scopes: ['https://database.windows.net//.default'],
-			redirectUri,
-			codeVerifier: connectionInfo?.proofKey,
-			clientInfo: connectionInfo?.externalBrowserQuery?.client_info || '',
-		};
-
-		const responseData = await pca.acquireTokenByCode(tokenRequest);
-
-		return responseData.accessToken;
-	} catch (error) {
-		logger.log('error', { message: error.message, stack: error.stack, error }, 'MFA MSAL auth error');
-		return '';
-	}
-};
-
-const getAgent = (reject, cert, key) => {
-	return new https.Agent({ cert, key, rejectUnauthorized: !!reject });
-};
-
-const getTokenByAxios = async ({ connectionInfo, tenantId, redirectUri, clientId, logger, agent }) => {
-	try {
-		const params = new URLSearchParams();
-		params.append('code', connectionInfo?.externalBrowserQuery?.code || '');
-		params.append('client_id', clientId);
-		params.append('redirect_uri', redirectUri);
-		params.append('grant_type', 'authorization_code');
-		params.append('code_verifier', connectionInfo?.proofKey);
-		params.append('resource', 'https://database.windows.net/');
-
-		const responseData = await axios.post(`https://login.microsoftonline.com/${tenantId}/oauth2/token`, params, {
-			headers: {
-				'Content-Type': 'application/x-www-form-urlencoded',
-			},
-			...(agent && { httpsAgent: agent }),
-		});
-
-		return responseData?.data?.access_token || '';
-	} catch (error) {
-		logger.log('error', { message: error.message, stack: error.stack, error }, 'MFA Axios auth error');
-		return '';
-	}
-};
-
-const getTokenByAxiosExtended = params => {
-	return getTokenByAxios({ ...params, agent: getAgent() });
-};
-
-const getToken = async ({ connectionInfo, tenantId, clientId, redirectUri, logger }) => {
-	const axiosExtendedToken = await getTokenByAxiosExtended({
-		connectionInfo,
-		clientId,
-		redirectUri,
-		tenantId,
-		logger,
-	});
-	if (axiosExtendedToken) {
-		return axiosExtendedToken;
-	}
-
-	const msalToken = await getTokenByMSAL({ connectionInfo, clientId, redirectUri, tenantId, logger });
-	if (msalToken) {
-		return msalToken;
-	}
-
-	const axiosToken = await getTokenByAxios({ connectionInfo, clientId, redirectUri, tenantId, logger });
-	if (axiosToken) {
-		return axiosToken;
-	}
-
-	return;
-};
+async function getTableRowCount(tableSchema, tableName, currentDbConnectionClient) {
+	const rowCountQuery = `SELECT COUNT(*) as rowsCount FROM [${tableSchema}].[${tableName}]`;
+	const rowCountResponse = await currentDbConnectionClient.query(rowCountQuery);
+	const rowCount = rowCountResponse?.recordset[0]?.rowsCount;
 
-const getAuthConfig = (clientId, tenantId, logger) => ({
-	system: {
-		loggerOptions: {
-			loggerCallback(loglevel, message) {
-				logger(message);
-			},
-			piiLoggingEnabled: false,
-			logLevel: msal.LogLevel.Verbose,
-		},
-	},
-	auth: {
-		clientId,
-		authority: `https://login.microsoftonline.com/${tenantId}`,
-	},
-});
+	return rowCount;
+}
 
 module.exports = {
 	getConnectionClient,
@@ -629,11 +496,3 @@ module.exports = {
 	queryDistribution,
 	getPartitions,
 };
-
-async function getTableRowCount(tableSchema, tableName, currentDbConnectionClient) {
-	const rowCountQuery = `SELECT COUNT(*) as rowsCount FROM [${tableSchema}].[${tableName}]`;
-	const rowCountResponse = await currentDbConnectionClient.query(rowCountQuery);
-	const rowCount = rowCountResponse?.recordset[0]?.rowsCount;
-
-	return rowCount;
-}
diff --git a/reverse_engineering/databaseService/helpers/connection.js b/reverse_engineering/databaseService/helpers/connection.js
new file mode 100644
index 0000000..6c6b684
--- /dev/null
+++ b/reverse_engineering/databaseService/helpers/connection.js
@@ -0,0 +1,263 @@
+const axios = require('axios');
+const sql = require('mssql');
+const https = require('https');
+const msal = require('@azure/msal-node');
+const { logAuthTokenInfo } = require('../../helpers/logInfo');
+const { prepareError } = require('./errorService');
+
+const logConnectionHostAndUsername = ({ hostname, username, authMethod, logger }) => {
+	logger.log(
+		'info',
+		`hostname: ${hostname ?? 'absent'}, username: ${username ?? 'absent'}, auth method: ${authMethod}`,
+		'Auth info',
+	);
+};
+
+class Connection {
+	constructor({ logger }) {
+		this.logger = logger;
+	}
+
+	async connect() {}
+}
+
+class ConnectionStringConnection extends Connection {
+	constructor({ connectionInfo, logger }) {
+		super({ logger });
+		this.connectionInfo = connectionInfo;
+	}
+
+	async connect() {
+		logConnectionHostAndUsername({ authMethod: this.connectionInfo.authMethod, logger: this.logger });
+		return sql.connect(this.connectionInfo.connectionString);
+	}
+}
+
+class UsernamePasswordConnection extends Connection {
+	constructor({ commonConfig, credentialsConfig, logger }) {
+		super({ logger });
+		this.commonConfig = commonConfig;
+		this.credentialsConfig = credentialsConfig;
+	}
+
+	async connect() {
+		logConnectionHostAndUsername({
+			hostname: this.commonConfig.hostName,
+			username: this.credentialsConfig.user,
+			authMethod: this.connectionInfo.authMethod,
+			logger: this.logger,
+		});
+		return sql.connect({
+			...this.commonConfig,
+			...this.credentialsConfig,
+			options: {
+				encrypt: true,
+				enableArithAbort: true,
+			},
+		});
+	}
+}
+
+class UsernamePasswordWindowsConnection extends Connection {
+	constructor({ connectionInfo, commonConfig, credentialsConfig, logger }) {
+		super({ logger });
+		this.connectionInfo = connectionInfo;
+		this.commonConfig = commonConfig;
+		this.credentialsConfig = credentialsConfig;
+	}
+
+	async connect() {
+		logConnectionHostAndUsername({
+			hostname: this.commonConfig.hostName,
+			username: this.credentialsConfig.user,
+			authMethod: this.connectionInfo.authMethod,
+			logger: this.logger,
+		});
+		return sql.connect({
+			...this.commonConfig,
+			...this.credentialsConfig,
+			domain: this.connectionInfo.userDomain,
+			options: {
+				encrypt: false,
+				enableArithAbort: true,
+			},
+		});
+	}
+}
+
+class AzureActiveDirectoryMFAConnection extends Connection {
+	constructor({ connectionInfo, commonConfig, tenantId, clientId, redirectUri, logger }) {
+		super({ logger });
+		this.connectionInfo = connectionInfo;
+		this.commonConfig = commonConfig;
+		this.tenantId = tenantId;
+		this.clientId = clientId;
+		this.redirectUri = redirectUri;
+	}
+
+	async connect() {
+		const token = await this.#getToken();
+		logAuthTokenInfo({ token, logger: this.logger });
+		logConnectionHostAndUsername({ authMethod: this.connectionInfo.authMethod, logger: this.logger });
+		return sql.connect({
+			...this.commonConfig,
+			options: {
+				encrypt: true,
+				enableArithAbort: true,
+			},
+			authentication: {
+				type: 'azure-active-directory-access-token',
+				options: {
+					token,
+				},
+			},
+		});
+	}
+
+	async #getToken() {
+		const axiosExtendedToken = await this.#getTokenByAxiosExtended();
+		if (axiosExtendedToken) {
+			return axiosExtendedToken;
+		}
+
+		const msalToken = await this.#getTokenByMSAL();
+		if (msalToken) {
+			return msalToken;
+		}
+
+		const axiosToken = await this.#getTokenByAxios();
+		if (axiosToken) {
+			return axiosToken;
+		}
+	}
+
+	#getTokenByAxiosExtended() {
+		return this.#getTokenByAxios({ agent: this.#getAgent() });
+	}
+
+	#getAgent(reject, cert, key) {
+		return new https.Agent({ cert, key, rejectUnauthorized: Boolean(reject) });
+	}
+
+	async #getTokenByAxios({ agent }) {
+		try {
+			const params = new URLSearchParams();
+			params.append('code', this.connectionInfo?.externalBrowserQuery?.code || '');
+			params.append('client_id', this.clientId);
+			params.append('redirect_uri', this.redirectUri);
+			params.append('grant_type', 'authorization_code');
+			params.append('code_verifier', this.connectionInfo?.proofKey);
+			params.append('resource', 'https://database.windows.net/');
+
+			const responseData = await axios.post(
+				`https://login.microsoftonline.com/${this.tenantId}/oauth2/token`,
+				params,
+				{
+					headers: {
+						'Content-Type': 'application/x-www-form-urlencoded',
+					},
+					...(agent && { httpsAgent: agent }),
+				},
+			);
+
+			return responseData?.data?.access_token || '';
+		} catch (error) {
+			this.logger.log('error', { message: error.message, stack: error.stack, error }, 'MFA Axios auth error');
+			return '';
+		}
+	}
+
+	async #getTokenByMSAL() {
+		try {
+			const pca = new msal.PublicClientApplication(this.#getAuthConfig());
+			const tokenRequest = {
+				code: this.connectionInfo?.externalBrowserQuery?.code || '',
+				scopes: ['https://database.windows.net//.default'],
+				redirectUri: this.redirectUri,
+				codeVerifier: this.connectionInfo?.proofKey,
+				clientInfo: this.connectionInfo?.externalBrowserQuery?.client_info || '',
+			};
+
+			const responseData = await pca.acquireTokenByCode(tokenRequest);
+
+			return responseData.accessToken;
+		} catch (error) {
+			this.logger.log('error', { message: error.message, stack: error.stack, error }, 'MFA MSAL auth error');
+			return '';
+		}
+	}
+
+	async #getAuthConfig() {
+		return {
+			system: {
+				loggerOptions: {
+					loggerCallback(loglevel, message) {
+						this.logger.log(message);
+					},
+					piiLoggingEnabled: false,
+					logLevel: msal.LogLevel.Verbose,
+				},
+			},
+			auth: {
+				clientId: this.clientId,
+				authority: `https://login.microsoftonline.com/${this.tenantId}`,
+			},
+		};
+	}
+}
+
+class AzureActiveDirectoryUsernamePasswordConnection extends Connection {
+	constructor({ connectionInfo, commonConfig, credentialsConfig, tenantId, clientId, logger }) {
+		super({ logger });
+		this.connectionInfo = connectionInfo;
+		this.commonConfig = commonConfig;
+		this.credentialsConfig = credentialsConfig;
+		this.tenantId = tenantId;
+		this.clientId = clientId;
+	}
+
+	async connect() {
+		logConnectionHostAndUsername({
+			hostname: this.commonConfig.hostName,
+			username: this.connectionInfo.userName,
+			authMethod: this.connectionInfo.authMethod,
+			logger: this.logger,
+		});
+		return sql.connect({
+			...this.commonConfig,
+			...this.credentialsConfig,
+			options: {
+				encrypt: true,
+				enableArithAbort: true,
+			},
+			authentication: {
+				type: 'azure-active-directory-password',
+				options: {
+					userName: this.connectionInfo.userName,
+					password: this.connectionInfo.userPassword,
+					tenantId: this.tenantId,
+					clientId: this.clientId,
+				},
+			},
+		});
+	}
+}
+
+const getConnection = ({ type, data }) => {
+	switch (type) {
+		case 'Username / Password':
+			return new UsernamePasswordConnection(data);
+		case 'Username / Password (Windows)':
+			return new UsernamePasswordWindowsConnection(data);
+		case 'Azure Active Directory (MFA)':
+			return new AzureActiveDirectoryMFAConnection(data);
+		case 'Azure Active Directory (Username / Password)':
+			return new AzureActiveDirectoryUsernamePasswordConnection(data);
+		default:
+			return new ConnectionStringConnection(data);
+	}
+};
+
+module.exports = {
+	getConnection,
+};