How to set unique constraint over multiple columns when any one can be null?

by

In sqlite, all null are differences.
I think the best way to solve this issue is to set column c not null with a special default value. Then use the default value (for example 0, ”) to represent null.

edit 1

you can easily extend this solution to any columns

create table test (
    a text not null default "",
    b text not null default "",
    c text not null default ""
);

More Related Contents:

  1. How do I unlock a SQLite database?
  2. “Insert if not exists” statement in SQLite
  3. How to delete or add column in SQLITE?
  4. How to get Top 5 records in SqLite?
  5. Insert new column into table in sqlite?
  6. How do you enable LIMIT for DELETE in SQLite?
  7. SQLite Schema Information Metadata
  8. How to create custom functions in SQLite
  9. What is the difference between SQLite integer data types like int, integer, bigint, etc.?
  10. is there a limit to the size of a SQLite database?
  11. How to generate all dates between two dates
  12. SQLITE_BUSY The database file is locked (database is locked) in wicket
  13. Does it matter what extension is used for SQLite database files?
  14. SQLite “INSERT OR REPLACE INTO” vs. “UPDATE … WHERE”
  15. How do I DROP a constraint from a sqlite (3.6.21) table?
  16. Sqlite over a network share [closed]
  17. How do I add a new column in between two columns?
  18. SQLite table constraint – unique on multiple columns
  19. What is the difference between related SQLite data-types like INT, INTEGER, SMALLINT and TINYINT?
  20. Modify a Column’s Type in sqlite3
  21. Case sensitive and insensitive like in SQLite
  22. How to have an automatic timestamp in SQLite?
  23. svn cleanup: sqlite: database disk image is malformed
  24. Truncate a SQLite table if it exists?
  25. SELECT INTO statement in sqlite
  26. How to display blob value using x’abc’ binary string literal syntax?
  27. Unable to load DLL sqlite3 in Universal Windows App running on Mobile
  28. Integration Testing Entity Framework code first with in-memory database
  29. DbFunctions.TruncateTime LINQ equivalent in EF CORE
  30. How to get the last index of a substring in SQLite?

Leave a Comment