What Is a Data Model

1. Structure of the data
   • Relational Model: Resembles an array of structs in C.
   • Semistructured Model: XML
2. Operations on the data
   • Relational Model: Relational algebra (SQL)
   • Semistructured Model: Path (e.g. n1.n2.n3.n4)
3. Constraints
   • Don’t see any major difference here. The semistructured model can say one element must exist under another element. While for the relational model, this is always true.