Prohibit users from updating a column if another column is null?

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I have mytable which has 3 integer fields: id, status, project_id.

I've told people that they should not progress status past 4 before assigning it a project_id value. Naturally people don't listen and then there are problems down the road.

Is there a way to return an error if someone tries to update from status 4 to 5 while project_id column is null? I still need people to be able to update status from 2 or 3 to status 4 regardless of it having a project_id.

You can use CHECK constraint as suggested by @stickbit if you need very simple checks.

If you need a more complicated logic, you can use TRIGGER functionality

CREATE FUNCTION check_status()
  RETURNS trigger AS
$mytrigger$
BEGIN
   IF OLD.status = 4 AND NEW.status >= 5 AND NEW.project_id IS NULL THEN
      RAISE EXCEPTION 'Project ID must be assigned before progressing to status 5';
   END IF;
   RETURN NEW;
END
$mytrigger$
LANGUAGE plpgsql;

CREATE TRIGGER project_id_check
BEFORE UPDATE ON "MyTable"
FOR EACH ROW EXECUTE PROCEDURE check_status();

Prevent update in column if not Null (trigger) - MSDN, Hi, I have a table (tDoc) with severeral columns. I want to prevent users to update columns FileName and PublicDoc. IF the value in the fields is  You can do this in Power Query pretty easily by adding a custom column with the following code: if Month[End Date] = null then Month [Approved Date] else Month [End Date] This will create a column that has no nulls and either the Month Approved Date or the Month End Date. You then can remove both the End Date and Approved date columns if you want.

How about a check constraint on the table:

CHECK (project_id IS NOT NULL OR status < 5)

SQL, CREATE TRIGGER i_Seller ON Seller AFTER INSERT AS IF EXISTS (SELECT NULL BEGIN; UPDATE s SET MidName = NULL FROM Seller s JOIN inserted i ON s. probably introduce a constraint to prevent the column from having a value: 2020 Stack Exchange, Inc. user contributions under cc by-sa. This answer about updating column from a part of another column in the same table. update T1 set domainname = (New value) --Example: (SELECT LEFT(TableName.col, CHARINDEX('@',TableName.col)-1) STRIPPED_STRING FROM TableName where TableName.col = T2.Emp_ID) from TableName T1 INNER JOIN TableName T2 ON T1.ID= T2.ID;

Understanding the New SQL: A Complete Guide, but they don't allow you to save their data until some future execution of your application. even to a module), there are no problems of interaction with other users. A column that is possibly nullable has the potential to be set to the null value by an Even if it is possibly nullable, however, other factors may prevent it from  Select NVL(Column_A, Column_B) From 'schema'.'table_name' The NVL( ) function is available in Oracle, and not in MySQL or SQL Server. This function is used to replace NULL value with another value.

The ABCs of Workflow for E-Business Suite Release 11i and Release 12, WHERE email_address is not null AND partition_id = 1; These updates will ensure most with email addresses and over 500 tables with the column EMAIL_ADDRESS. instead of the email addresses in the employee, user or other tables records. To avoid a buildup of records in this queue, disable the Subscription  =Table.ReplaceValue(#"Last Step",null, each _[Values Column],Replacer.ReplaceValue,{"Null Column"}) #"Last Step" being the previous step in your query [Values Column] being the column that has the values in it to replace the nulls "Null Column" being the column with the null values

Beginning SQL Server 2005 Express for Developers: From Novice to , By default, all user-created databases in Microsoft SQL Server 2005 are enabled for fulltext indexing. 'disable' GO There will be times when columns We look at NULL values in Chapter 5 during our table creation discussion. ALTER If set to ON, this option makes every column of data contain the maximum number of  When explicitly updating a member column of the column set, the corresponding bit for that column is set to 1, and the column set bit is set to 1. When a explicitly updating a column set, the column set bit is set to 1, and the bits for all of the sparse columns in that table are set to 1. For insert operations, all bits are set to 1.

Hacker's Guide to Visual FoxPro 6.0, F. Date Check whether eBxpr contains the empty date { / / ) DateTime Check wait window "Enter a numeric value" End IF See Also IsBlank(), IsMull(), Set Exact, If you disable the control in a column of a grid, then click on that control, the grid the responses of the user, you can both encourage and shepherd the users  Assuming that you have a Get Item action before the Update Item action, try setting the value of the column when updating the item to the value retrieved from Get Item. In other words, reference the column value from the Get Item Dynamic properties. If this addresses your issue, please mark your post as Solved.

Comments
  • This seems like the way to go if the data wasn't already messed up. It says that rows are violating the check. I'll go with the below solution, thanks
  • @Luffydude If the data is already messed up, you really should clean your data. Put the new constraints/triggers in first, then go back and clean the data.
  • @AleksG if you have time to clean 1k rows then let me know, people will fix their data eventually. At the moment the NOT VALID suggested below is enough to make your query work