System.DateTime and Sql datetime2 in Linq2Sql (using sqlmetal)

Question

I'd like to utilize new Sql datetime2 data type for event logging (as standard datetime has lower precision than System.DateTime causing data loss on storing) but when i generate the code with sqlmetal.exe i get the following warning:

db.dbml(98) : Warning DBML1008: Mapping between DbType 'DateTime2(7) NOT NULL' and Type 'System.DateTime' in Column 'CreatedOn' of Type 'Event' may cause data loss when loading from the database.

The warning disappears if i change my column definition to datetime2(2) but 2 digits precision is lower than System.DateTime can handle, right? Why? How can i suppress the warning?

do you have .net framework 3.5 SP1 installed? – manji Mar 24 '11 at 20:33 — manji, Mar 24 '11 at 20:33
i do. but by primary target is .net4 – UserControl Mar 24 '11 at 21:57 — UserControl, Mar 24 '11 at 21:57

jaraics · Accepted Answer · 2011-03-30T20:18:42.617

4

You might just ignore that warning. I've checked the source of sqlmetal (using Reflector) and found this:

case SqlDbType.DateTime2:
if (scale <= 2)
  return Compatibility.Compatible;
else
  return Compatibility.DataLossFromDatabase;

However, querying a datetime2 field from a sample database returned the whole 7 digit precision.

edited Mar 30 '11 at 20:18

answered Mar 30 '11 at 17:56

jaraics

4,239
3
30
35

Is there a way to suppress it? – UserControl Mar 31 '11 at 07:19
I don't see any ways to suppress it (at least not in the current version, 3.5.30729.1) – jaraics Mar 31 '11 at 08:28

score 1 · Answer 2 · answered Mar 30 '11 at 04:14

1

SQLMetal is just a tool to generate your dbml file so it has no effect on runtime behaviour. But as a generation tool it may not be aware of the new datatype.

Have you tried editing the DBML yourself using an XML editor to see if you lose precision?

answered Mar 30 '11 at 04:14

Christian Maslen

1,100
9
13

System.DateTime and Sql datetime2 in Linq2Sql (using sqlmetal)

2 Answers2