The difference between data integration and data unification is best analyzed through data warehouse. Data warehouse is a widely used technology and is often covered to help companies with reporting speed and storage issues. Data unification is something that data warehouse does with ease as it is designed to collect information from many sources to speed up reports and store data. All data is in the same place and adapted for reporting processes.
Just pulling all the data from the source systems and placing it in the warehouse doesn’t mean necessarily business logic can be easily restored. Recovering and quantifying business logic also means data is integrated, not just collected in one place as data unification or a single point of truth. It is not easy to recover the business logic within the data set, since the flow of data on production systems is usually not large enough to describe processes for reporting purposes. Insufficient data flow and missing data are the main reasons why data warehouse cannot provide integrated data, only unified data by default. The business side usually misinterprets two terms and assumes that implementing warehouse will solve all problems in reports. Core reporting problems lie at the production level with insufficient data exchange between systems that Warehouse cannot solve. “Garbage in” also means “garbage out”.
An example of integrated data is shown in the following case. Number of customers who bought marketing package A. The total number of marketing packages currently sold A should be closely related to the difference between the current and last month of newly connected and disconnected packages. The total number of packages should be integrated with newly sold and no longer used packages, so-called churners. If production systems and billing are only set up for processes, this can mean that the company bills the service correctly, but may not report the service reliably. Production systems are typically set up for processes, not reports. If reports are not implemented immediately during the deployment phase of the production system, additional implementation of reporting techniques into the live production system is far more difficult. Integration is not the same as unification.
It is deeper and more difficult to achieve integration than simply implementing data warehouse and unifying data.