Why does my audit trail code cause a concurrency error? - oracle

Question

The environment is React, .NET Core 2.2.5, Oracle EF Core 2.19.30, Oracle 12c.
I am using the following code to add change log entries whenever an entity is changed in some way. Everything I've seen on Google indicates this should work. However, when it gets to the "base.SaveChanges()" call, I get the error "database operation expected to affect 1 row(s) but actually affected 5 row(s)". If I remove the change log code and just call "base.SaveChanges()", it works fine and does update the expected row, so the issue is clearly related to the change log entries itself.
I've seen this error on Google, but the actual number is always 0, never more. The other strange thing is that every time I run the code, the "actual" number increases by 5 (I'm up to 95 at the moment, and that's after I rebooted), which does happen to be the number of change log entries that should be added.
I don't see anything unusual in my situation, other than I'm using Oracle (I plan on testing this with SQL Server at home soon).
public override int SaveChanges()
{
List<EntityEntry> entries = ChangeTracker.Entries().Where(x => x.State == EntityState.Added || x.State == EntityState.Modified || x.State == EntityState.Deleted).ToList();
foreach (EntityEntry entry in entries.ToArray())
{
string tableName = new SafetyDataContext().Model.FindEntityType(entry.Entity.GetType()).Relational().TableName;
string keyData = GetPrimaryKeyValue(entry);
if (entry.State == EntityState.Added)
{
PropertyValues currentValues = entry.CurrentValues;
for (int i = 0; i < currentValues.Properties.Count; i++)
{
string columnName = currentValues.Properties[i].Relational().ColumnName;
string newValue = currentValues[currentValues.Properties[i].Name] != null ? currentValues[currentValues.Properties[i].Name].ToString() : string.Empty;
EntityChangeModel log = new EntityChangeModel()
{
Change_Type = "ADD",
Change_Date = DateTime.Now,
Change_User_ID = 0,
Table_Name = tableName,
Column_Name = columnName,
Primary_Key = keyData,
Old_Value = string.Empty,
New_Value = newValue
};
this.Changes.Add(log);
}
}
else if (entry.State == EntityState.Modified)
{
PropertyValues currentValues = entry.CurrentValues;
PropertyValues originalValues = entry.OriginalValues;
for (int i = 0; i < currentValues.Properties.Count; i++)
{
string columnName = currentValues.Properties[i].Relational().ColumnName;
string oldValue = entry.GetDatabaseValues().GetValue<object>(originalValues.Properties[i].Name) != null ? entry.GetDatabaseValues().GetValue<object>(originalValues.Properties[i].Name).ToString() : string.Empty;
string newValue = currentValues[currentValues.Properties[i].Name] != null ? currentValues[currentValues.Properties[i].Name].ToString() : string.Empty;
if (oldValue != newValue)
{
EntityChangeModel log = new EntityChangeModel()
{
Change_Type = "CHANGE",
Change_Date = DateTime.Now,
Change_User_ID = 0,
Table_Name = tableName,
Column_Name = columnName,
Primary_Key = keyData,
Old_Value = oldValue,
New_Value = newValue
};
this.Changes.Add(log);
}
}
}
else if (entry.State == EntityState.Deleted)
{
PropertyValues originalValues = entry.OriginalValues;
for (int i = 0; i < originalValues.Properties.Count; i++)
{
string columnName = originalValues.Properties[i].Relational().ColumnName;
string oldValue = entry.GetDatabaseValues().GetValue<object>(originalValues.Properties[i].Name) != null ? entry.GetDatabaseValues().GetValue<object>(originalValues.Properties[i].Name).ToString() : string.Empty;
EntityChangeModel log = new EntityChangeModel()
{
Change_Type = "DELETE",
Change_Date = DateTime.Now,
Change_User_ID = 0,
Table_Name = tableName,
Column_Name = columnName,
Primary_Key = keyData,
Old_Value = oldValue,
New_Value = string.Empty
};
this.Changes.Add(log);
}
}
}
return base.SaveChanges();
}