If you’re getting an error that reads something like “Computed column ‘c3’ in table ‘t1’ cannot be persisted because the column is non-deterministic” in SQL Server, it appears that you’re trying to persist a computed column that’s nondeterministic.
A nondeterministic function or expression returns a different result for the same input. If a column uses such an expression, then it will be nondeterministic. A computed column must be deterministic.
Continue readingIf you’re getting an error that reads something like “Computed column ‘c2’ in table ‘t1’ is not allowed to be used in another computed-column definition” in SQL Server, it appears that you’re trying to create a computed column that uses another computed column.
We can’t use other computed columns in our computed column definitions.
Continue readingIf you’re getting an error that reads something like “Cannot alter column ‘c2’ because it is ‘COMPUTED’” in SQL Server, it looks like you’re trying to alter a computed column.
We can’t alter computed columns.
Continue readingIn SQL Server we can run a query against the sys.computed_columns system catalog view to return all computed columns and their definitions.
If you’re not sure if a table has a generated column in SQLite, you can quickly find out with either the .schema command, or by querying the sqlite_schema table.
If you have a table in MariaDB with a generated column, you can use the following methods to find out its definition.
Continue readingHere are five ways to see whether a table contains a generated column in MariaDB.
Continue readingIf we need to add a virtual column to an existing table in Oracle Database, we can do so with the usual SQL ALTER TABLE statement.
MySQL supports generated columns. If you’re not sure whether a table has a generated column or not, you can check it using any of the following methods.
Continue readingA generated column is a database column whose value is an expression. Therefore, the value of the generated column is usually derived (for example, it could be derived from values in other columns).
Generated columns are also sometimes referred to as computed columns or virtual columns.
Creating a generated column in MariaDB is essentially the same as creating a normal column. The difference is that the definition of the generated column contains an expression that determines the column’s value.
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