Nowdays, modern applications often use blockchains as a secure data store. However, querying blockchain data is more challenging than querying conventional databases due to blockchains being primarily designed for the logging of asset transfers, such as cryptocurrencies, rather than storing and reading generic data. To improve the experience of querying blockchain data and make it comparable to querying conventional databases, new design approaches of the storage engine for blockchain technology are required. An important aspect is the data layout of a block, as it plays a crucial role in facilitating reading of blockchain data. In this paper, we identify a suitable data layout that provides the required query capabilities while preserving the key properties of blockchain technology. Our goal is to overcome the limitations of current data access models in blockchains, such as the reliance on auxiliary data storages and error-prone smart contracts. To this end, we compare four promising data layouts with data models derived from document, row, column, and triple stores in terms of schema flexibility, read pattern generality, and relational algebra suitability. We then assess the most suitable data layout for blockchain technology.