| Feature | DB2 | VSAM |
| Hardware | PC to mainframe | Only Mainframe |
| OS | NT, Unix & OS/390 | Only OS/390 |
| Vendor | RBDMS with ANSI std. | Only IBM |
| Scalability | PC to mainframes Upto 4000 terabytes for LOB | Only Mainframe Maximum size is 128 terabytes |
| Ease of development | Standard SQL Stored procedure & triggers | Not so simple No such option |
| Ease of maintenence | Standard SQL | Difficult |
| Security | High degrees of security | Only at Dataset level |
| Referential Integrity | DB2 enforces it Manages even externally stored data | Developers responsibility Not applicable |
| Query Interface | Easy to view/modify | Not available |
| Products/tool suite | IBM & 3rd Parties | Not available |
| Data Capacity | 254 times largest VSAM | Limited to 2 terabytes |
| Data sharing | Across CICS, IMS, Batch, TSO | Very limited support |
| Web & Java support | JDBC, SQLJ, Net.data | Need custom interfaces |
| Distributed environment | Consistent across platforms Stored procs reduce network traffic | Only Mainframe Not applicable |
| XML support | XML extenders | Not supported |
| Performance | For less data Better for large data Optimizer handles Partitioning improves performance | Better when data is less For less data Developer responsible No partitioning |
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