feat: refactor db handling to use db-wrapper package; enhance connection management and result handling for MSSQL and Postgres

internal/app/db-wrapper/postgres.go

@@ -15,16 +15,24 @@ func init() {
 }
 
 type postgresRowResult struct {
+	row pgx.Row
+}
+
+func (pr *postgresRowResult) Scan(dest ...any) error {
+	return pr.row.Scan(dest...)
+}
+
+type postgresRowsResult struct {
 	columns []string
 	rows    pgx.Rows
 }
 
-func (pr *postgresRowResult) Close() error {
+func (pr *postgresRowsResult) Close() error {
 	pr.rows.Close()
 	return nil
 }
 
-func (pr *postgresRowResult) Columns() ([]string, error) {
+func (pr *postgresRowsResult) Columns() ([]string, error) {
 	if pr.columns != nil {
 		return pr.columns, nil
 	}
@@ -42,19 +50,19 @@ func (pr *postgresRowResult) Columns() ([]string, error) {
 	return columns, nil
 }
 
-func (pr *postgresRowResult) Err() error {
+func (pr *postgresRowsResult) Err() error {
 	return pr.rows.Err()
 }
 
-func (pr *postgresRowResult) Next() bool {
+func (pr *postgresRowsResult) Next() bool {
 	return pr.rows.Next()
 }
 
-func (pr *postgresRowResult) Scan(dest ...any) error {
+func (pr *postgresRowsResult) Scan(dest ...any) error {
 	return pr.rows.Scan(dest...)
 }
 
-func (pr *postgresRowResult) Values() ([]any, error) {
+func (pr *postgresRowsResult) Values() ([]any, error) {
 	return pr.rows.Values()
 }
 
@@ -102,7 +110,12 @@ func (pw *postgresDbWrapper) Query(ctx context.Context, query string, args ...an
 		return nil, err
 	}
 
-	return &postgresRowResult{columns: nil, rows: rows}, nil
+	return &postgresRowsResult{columns: nil, rows: rows}, nil
+}
+
+func (pw *postgresDbWrapper) QueryRow(ctx context.Context, query string, args ...any) RowResult {
+	row := pw.db.QueryRow(ctx, query, args...)
+	return &postgresRowResult{row: row}
 }
 
 func (pw *postgresDbWrapper) SaveMassive(ctx context.Context, schema string, table string, columnNames []string, rows [][]any) (int64, error) {