> For the complete documentation index, see [llms.txt](https://docs.graph.build/EGeX4aTAJLlpg9Hh8kfl/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.graph.build/EGeX4aTAJLlpg9Hh8kfl/graph.build-studio/modelling-multiple-semi-structured-source-files.md).
# Modelling Multiple Semi Structured Source Files
The Semi-Structured Transformer allows up to five different source data files to be used within a single model. Relationships (edges) can be created between entities (nodes) from different sources. However, to prevent the relationship from generating a Cartesian product—where every instance of node type X is linked to every instance of node type Y—a join condition is required. The join condition ensures that an edge or relationship is only created when a specified field from each source file contains matching values.
In the example below, two source files are used: one containing transaction data and another containing person and card data.
* The `Transaction` and `Location` nodes are sourced from the `new-transactions.csv` file.
* The `Person` node is sourced from the `person-card.json` file.
An edge has been created to link the `Person` node to the `Location` node using the `madeTransactionIn` relationship. To ensure that edges are only created between people and their relevant transaction data, a join condition must be specified on the edge.
In this case, the `if` and `equals` fields are used to select data from each source file. Both files contain credit card numbers, so edges will only be created between nodes for records where the card numbers match.
