Master Data
Master data is the central, long-lived core data of a company – such as items, customers, suppliers and accounts. It describes the permanent objects of a business and forms the foundation in the ERP system on which all business processes are built.
Master data is the central, long-term core data of a company that describes its permanent objects: items, customers, suppliers, employees, accounts or storage locations. It changes only rarely and is not created by individual business transactions, but set up once and then maintained. In the ERP system, master data forms the reference layer that every process accesses – from purchasing through order processing to accounting.
The concept is clearly distinct from transaction data, which arises from ongoing operations (orders, delivery notes, invoices, postings). While an invoice documents a one-time event, the associated customer master record describes a lasting business relationship. Master data thus provides the stable frame of reference within which the changing transaction data moves. Its quality directly determines the reliability of all downstream processes – flawed master data propagates into every document that references it.
At a glance
- Central, long-lived core data: items, customers, suppliers, accounts, employees
- Set up once and maintained – not created by business transactions
- The counterpart to transaction data (documents, postings, orders)
- Forms the reference layer for all processes in the ERP
- Data quality determines process reliability, reporting and compliance
The types of master data
Master data can be structured by the objects it describes. The most common are the partner and material masters, which carry the core of operational processes. In addition, there are organisational and accounting master data that work more in the background but are just as permanently established.
The most important categories include the item master (also material master) with product data such as item number, description, units, prices and weights; the customer master with addresses, payment and delivery terms; and the supplier master with sources of supply and purchasing terms. Alongside these are financial master data such as the chart of accounts, cost centres and tax keys, personnel master data, and technical-organisational master data such as storage locations, units of measure or payment terms.
Partner master data vs. material master data
Partner master data describes a company’s business partners – essentially the customer master and supplier master. Material master data (item master), by contrast, describes the objects traded or produced. Both are combined in documents: an order links a customer from the partner master with one or more items from the material master. This separation keeps the data models lean and avoids redundancy.
Master data vs. transaction data – the distinction
The most important conceptual boundary runs between master data and transaction data. Master data is inventory-oriented and stable over time: an item or a customer exists independently of individual transactions and retains its identity for years. Transaction data, by contrast, is process-oriented and transient – it arises continuously from business transactions and documents individual events at a specific point in time.
An example illustrates the interplay: the customer master record "Muster GmbH" is a piece of master data. When this customer orders goods, an order, a delivery note and an invoice result from it – all transaction data that references the master record. If the customer changes their address, the master data is updated; the documents already generated remain unchanged as historical transaction data. Some models additionally recognise inventory data (such as the current stock level) and configuration or reference data (settings, number ranges) that lie between the two poles.
Why master data is so important in the ERP
In the ERP system, master data is the foundation on which all modules are built. Because purchasing, warehouse, sales, production and financial accounting access the same central master records, an item or a customer needs to be maintained only once and is then consistently available system-wide. This single maintenance ("single source of truth") prevents contradictory data sets and is one of the core advantages of an integrated ERP over isolated point solutions.
The flip side: errors in the master data have system-wide effects. An incorrectly stored tax key distorts every invoice, an outdated weight in the item master leads to wrong shipping costs, a duplicated customer address skews reporting and credit checks. Poor master data quality is therefore one of the most common causes of process disruptions and wrong decisions. Conversely, clean, complete and unambiguous master data is the prerequisite for automation, reliable reporting and the smooth connection of shops and marketplaces via interfaces.
Master data maintenance and data governance
For master data to remain reliable over the long term, it requires defined responsibilities and maintenance processes – often under the term master data management (MDM). This includes naming conventions, mandatory fields, duplicate checks, approval workflows and clear accountability (data ownership). Without such rules, master data drifts apart over time, especially when several departments or systems maintain the same objects.
Master data in migration and ERP implementation
When introducing or switching an ERP system, master data is regularly the most demanding and delicate part of the migration. It must be extracted from legacy systems, cleansed, merged free of duplicates and transferred into the structure of the new system. Because data sets that have grown over time often contain dead records, typos and inconsistent formats, the principle applies: no migration without prior data cleansing. Carrying poor data into a new system merely relocates the problem.
A proven approach is to treat the migration as a self-contained sub-project: map data fields, run test imports, review the results from a business perspective and only then go live. For ongoing data flows between systems – for example between the ERP and an online shop – interfaces and a defined leading system of record ensure that master data stays in sync and changes do not have to be maintained multiple times.
DACH specifics and compliance
In the German-speaking region, certain master data is subject to legal requirements. Accounting-relevant master data such as the chart of accounts, tax keys or accounts receivable and payable must match the requirements of the GoBD and the DATEV structure so that postings are processed correctly and in an audit-proof manner. The VAT identification number in the customer and supplier master is also relevant for intra-community supplies and correct tax determination.
Personal master data – such as customer and employee data – additionally falls under the GDPR. This concerns purpose limitation, deletion concepts and rights of access: an ERP must not only store personal master data but also be able to block and delete it in a controlled way once there is no longer a retention obligation. Cleanly structured master data with clear fields for tax and legal attributes makes it considerably easier to meet these requirements in day-to-day operations.
Example
Example: master data chaos at a growing online retailer
A retailer of office supplies maintained its item and customer data for years in parallel in a shop system, an Excel price list and an accounting program. Because the same item carried different numbers and descriptions depending on the system, and customers were created multiple times with slightly differing addresses, there were regular incorrect deliveries, faulty invoices and unusable revenue reports per customer.
With the introduction of an ERP system, the master data was first consolidated: items received unique numbers, duplicates in the customer master were merged, tax keys and payment terms were standardised. Since then, there is exactly one master record per item and customer, accessed jointly by the shop, warehouse and accounting. The result: correct documents, reliable reporting and considerably less manual rework – the demanding part was not the software, but cleaning up the master data beforehand.
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