Using LINQ, how do I insert a null value into a SQL Server 2008 DateTime column?
The code below inserts "1/1/1900 12:00:00 AM",
But I want to insert "NULL" instead
CreatDate = System.Data.SqlTypes.SqlDateTime.Null
Ensure that the column in the DB is set to allow NULL and your entity property, "CreateDate" is defined as "DateTime? CreateDate {get;set;}". Then, simply set "CreateDate = null".
Your CreateDate property needs to be declared Nullable<DateTime> (aka DateTime?). Then, you can set that property on your Linqed-up object to null (not System.Data.SqlTypes.SqlDateTime.Null, just plain old C# null) and you should get the desired result. This of course assumes that your SQL table has the column properly defined to allow NULLs and that your definition for the column in the DBML also allows them.
Related
From a query I want to replace the null values of the "cod_account" field, the condition to fill this field is that it must take the previous value only if it satisfies that the previous records of other fields (cod_agen, cod_sub, no_prod) are equal.
Currently it is like this:
enter image description here
what is desired is
enter image description here
thanks for your advice. i solve it
use with to separate queries.
select
case when cod_account is null and class ='Primary'
then null
when cod_account is null and class='Secundary'
then (select cod_account from principals P--principals is table create in a "with"
where fa.cod_agen=P.cod_agen
and fa.cod_sub=P.cod_sub
and fa.no_prod=P.no_prod
and p.class='secundary'
)
...
from signs fa
From the documentation, you have to put a NOT NULL modifier in the column definition to mark it as such, just like for other SQL databases.
Consider this table:
CREATE TABLE test (
name String NOT NULL,
isodate DateTime('Europe/Berlin') NOT NULL
) ENGINE = MergeTree()
ORDER BY (isodate)
If I would try to insert NULL for both columns (or at least one), the expected behaviour is that Clickhouse declines insertion since the columns are marked as NOT NULL. Instead, Clickhouse creates a new row, where isodate is 1970-01-01 01:00:00 and name is an empty string, which are the default values for those data types apparently.
What do I have to do so that Clickhouse declines such inserts?
My Clickhouse server version is 21.12.3.
In ClickHouse, NULL and NOT NULL do change the behavior of the data type, but not in the way other relational databases - it is syntactically compatible with other relational database but not semantically (a Int32 NULL is the same as a Nullable(Int32), as a Int32 NOT NULL is the same as a Int32). A column defined as NOT NULL does not mean it will refuse to insert fields whose values are NULL in the insert statement - it means ClickHouse will use the default expression for the column type (or if it is not specified in the column definition, the default value for the data type). This behavior is expected in ClickHouse when input_format_null_as_default is enabled (the default for Clickhouse 21.12.3).
To throw exceptions for such invalid values you need to change the system setting input_format_null_as_default to 0. If you use clickhouse-client, you can disable it while connecting to clickhouse:
clickhouse-client -h ... --input_format_null_as_default 0
or after:
clickhouse> SET input_format_null_as_default=0
This way, a statement like insert into test (name, isodate) values (NULL, NULL); will behave more likely most relational databases.
Clickhouse behaviour with Not Null constraints is not compatible with other databases.
You can overcome it using check constraints https://clickhouse.com/docs/en/sql-reference/statements/create/table/#constraints
CREATE TABLE test (
name String NOT NULL,
isodate DateTime('Europe/Berlin') NOT NULL,
CONSTRAINT isodate_not_null CHECK isodate <> toDateTime(0, 'Europe/Berlin')
) ENGINE = MergeTree()
ORDER BY (isodate)
insert into test(name) values ('x');
DB::Exception: Constraint `isodate_not_null` for table default.test (f589312a-1592-426a-b589-312a1592b26a) is violated at row 1. Expression: (isodate != toDateTime(0)). Column values: isodate = 0. (VIOLATED_CONSTRAINT)
insert into test values ('x', now());
OK.
The reason is performance, in OLAP databases need to ingest data as fast as possible.
I have created table with single column having data type -dateTimeOffset value and inserted some values.
create table dto (dto datetimeoffset(7))
insert into dto values (GETDATE()) -- inserts date and time with 0 offset
insert into dto values (SYSDATETIMEOFFSET()) -- current date time and offset
insert into dto values ('20131114 08:54:00 +10:00') -- manual way
In Nifi,i have specified "Select * from dto" query in Execute SQL .
It shows below error..,
java.lang.IllegalArgumentException: createSchema: Unknown SQL type -155 cannot be converted to Avro type
If i change that column into dateTime then ExecuteSQL runs correctly but it doesn't worked in DateTimeOffset column.
Any help appreciated.
Many thanks
datetimeoffset is a MSSQL-specific JDBC type and is not supported by ExecuteSQL (which supports the standard JDBC types). You could try to cast the datetimeoffset field into some other standard type such as datetime, as described here.
I've created a Custom Processor and adapted the JdbcCommon.java class to include SQL Server's DATETIMEOFFSET. It's just one line of code. I'll try to see if I can ask them to merge this on the official repo.
This is a piece of my JdbcCommon.java:
case TIMESTAMP:
case TIMESTAMP_WITH_TIMEZONE:
case -101: // Oracle's TIMESTAMP WITH TIME ZONE
case -102: // Oracle's TIMESTAMP WITH LOCAL TIME ZONE
case -155: // SQL Server's DATETIMEOFFSET <---- added this line
addNullableField(builder, columnName,
u -> options.useLogicalTypes
? u.type(LogicalTypes.timestampMillis().addToSchema(SchemaBuilder.builder().longType()))
: u.stringType());
break;
why I am getting this error ?
In the table DDL I only have 2 columns , id (number) and name (varchar)
ALTER TABLE mytable ADD SUSPEND date NOT NULL
ORA-01758: table must be empty to add mandatory (NOT NULL) column
ORA-06512: at line 7
ORA-01758: table must be empty to add mandatory (NOT NULL) column ORA-06512: at line 7
And is your table empty? I think not.
There's probably a way around this involving adding the column as nullable, then populating every row with a non-NULL value, the altering the column to be not null.
Alternatively, since the problem is that these current rows will be given NULL as a default value, and the column is not allowed to be NULL, you can also get around it with a default value. From the Oracle docs:
However, a column with a NOT NULL constraint can be added to an existing table if you give a default value; otherwise, an exception is thrown when the ALTER TABLE statement is executed.
Here is a fiddle, how you could do it
Would a date in the future be acceptable as a temporary default? If so, this would work:
ALTER TABLE MYTABLE ADD (SUSPEND_DATE DATE DEFAULT(TO_DATE('21000101', 'YYYYMMDD'))
CONSTRAINT SUSPEND_DATE_NOT_NULL NOT NULL);
If table already contain the records then table won't allowes to add "Not null" column.
If you need same then set default value for the column or truncate the table then try.
I have a EmployeeID parameter:
="[Employee].[Employee Id].&[12345678912345]"
I have a SQL query that calls for EmployeeID parameter like this:
Where...AND (EmployeeID = #EmployeeID)
I then go into the sql dataset's parameters list and set EmployeeID's value to:
=LEFT(RIGHT(Parameters!EmoloyeeID.Value,15),14)
This should give 12345678912345. EmployeeID column in SQL table has datatype of nvarchar(25).
Now when I use lookup to connect Cube's dataset (dataset of the tablix I am working on) with this SQL dataset,
=Lookup(Cube's EmployeeName field, SQL's EmployeeName field, SQL's EmployeeStatus, "SQLDataSet")
I get no output. I get blank. (I know for fact that there is data because when I execute SQL query in SSMS with EmployeeID declared to 12345678912345, I get right EmployeeeName (matches with Cube's EmployeeName value) and EmployeeStatus values.
What am I doing wrong? Am I doing something wrong to EmployeeID parameter's value manipulation?
Is this a typo?
=LEFT(RIGHT(Parameters!EmoloyeeID.Value,15),14)
Just want to check to ensure it's not a simple fix :-)