accuracy<\/a> of the .Net date is likely to be less than 100 nanoseconds.<\/p>\n\n\n\nThis difference in accuracy is not normally a problem but it can be difficult in testing when you might wish to write a value to the database and then read it to check it has been saved correctly: a DateTime will likely not be the same as the value saved as it will have been rounded.<\/p>\n\n\n\n
The function below is an attempt to replicate the rounding performed by SQL Server:<\/p>\n\n\n\n
\/\/\/ <summary>\n\/\/\/ Rounds a DateTime as it would be changed by SQL.\n\/\/\/ <\/summary>\n\/\/\/ <remarks>\n\/\/\/ The .Net DateTime is accurate to 0.1 milliseconds (100 nanoseconds). SQL Server DateTime is \"Rounded to increments\n\/\/\/ of .000, .003, or .007 seconds\" i.e. 0, 3 or 7 milliseconds.\n\/\/\/ <\/remarks>\npublic static DateTime DateTimeAsFromSql(DateTime dateTime)\n{\n\tDateTime rounded = new DateTime(dateTime.Year, dateTime.Month, dateTime.Day, dateTime.Hour, dateTime.Minute, dateTime.Second);\n\tlong ticksDifference = dateTime.Ticks - rounded.Ticks;\n\tint milliseconds = ((int)(ticksDifference \/ 100000)) * 10;\n\tlong ticks = ticksDifference - (milliseconds * 10000);\n\tif (ticks >= 0 && ticks < 17000)\n\t{\n\t\tmilliseconds += 0;\n\t}\n\telse if (ticks >= 17000 && ticks < 50000)\n\t{\n\t\tmilliseconds += 3;\n\t}\n\telse if (ticks >= 50000 && ticks < 84000)\n\t{\n\t\tmilliseconds += 7;\n\t}\n\telse if (ticks >= 84000 && ticks <= 99999)\n\t{\n\t\tmilliseconds += 10;\n\t}\n\telse\n\t{\n\t\tthrow new InvalidOperationException(\"ticks: \" + ticks);\n\t}\n\n\treturn rounded.AddMilliseconds(milliseconds);\n}\n<\/code><\/pre>\n\n\n\nOf course, a better solution is to use one of the other SQL date formats that allow for more precision.<\/p>\n","protected":false},"excerpt":{"rendered":"
The SQL Server DateTime type is represented by LINQ to SQL as a .Net System.DateTime type. This presents a small problem in that the .Net type supports more precision – a “tick” representing 100 nanoseconds – than the SQL type which is “rounded to increments of .000, .003, or .007 seconds”. It is worth noting […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[2,12],"class_list":["post-148","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-net","tag-sql-server"],"_links":{"self":[{"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/posts\/148","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=148"}],"version-history":[{"count":4,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/posts\/148\/revisions"}],"predecessor-version":[{"id":152,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=\/wp\/v2\/posts\/148\/revisions\/152"}],"wp:attachment":[{"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=148"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=148"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thedifficultbit.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=148"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}