What types of errors or inconsistencies can occur when transactions are executed simultaneously?

When executing transactions simultaneously, the following types of errors and inconsistencies may occur:

• Dirty Read: a transaction reads data that has been modified but not yet committed by another transaction.
• Non-repeatable Read: when reading the same data multiple times within a transaction, it may change due to another transaction.
• Phantom Read: when re-executing a query, new rows added by another transaction appear.
• Locks and Deadlocks: transactions may block each other, waiting for resources to be released.

In Go, when working with databases, it is important to use the correct transaction isolation level and synchronization mechanisms to prevent such issues.