We have a number of options when it comes to returning a list of sequences in PostgreSQL. By “sequences”, I mean “sequence objects”, or “sequence generators”. These are objects we can create in order to generate a series of sequential numbers.
Here are three ways to get a list of sequences in Postgres.
Continue readingIf you’re getting an error that reads something like “nextval: reached minimum value of sequence “sequence1” (-3)” in PostgreSQL, it’s probably because you’re trying to generate a new value from a descending sequence, but the sequence has already reached its minimum value.
We have a number options when it comes to dealing with this issue.
Continue readingWhen we create a sequence in PostgreSQL, we have the option of making it a non-repeating sequence or repeating sequence.
By “repeating” sequence, I mean that, once it reaches its maximum value (or minimum if it’s a descending sequence), it starts all over again, re-using numbers previously generated.
Continue readingIn SQL Server, we can use the sp_sequence_get_range stored procedure to generate a range of sequence numbers from a sequence object.
One common use case for sequences in SQL Server is to use them to number the results of a query. For example, we can add a column that has a number that increments with each row, similar to a row counter (but with a sequence that we define).
Continue readingIf you’re getting an error that reads something like “MINVALUE (1) must be less than MAXVALUE (1)” in PostgreSQL when you’re trying to create a sequence, it’s probably because your sequence’s minimum possible value is higher than the maximum value.
To fix this issue, be sure that the sequence’s maximum value is greater than the minimum value.
Continue readingIn SQL Server, we can create sequence objects in order to generate a range of numbers that increment with each call to the sequence.
Although sequences are similar to identity columns, they are different in that they are generated independently of any table. It’s up to the application to generate the next sequence number before inserting it into the table. Therefore, we can apply a sequence to a table in the same way we would insert any other data into a table.
Here are two ways to apply sequence numbers into a table in SQL Server.
Continue readingIn SQL Server, we can use the sys.sequences system catalog view to return a list of sequence objects in the current database.
If you’re getting an error that reads something like “START value (101) cannot be greater than MAXVALUE (100)” in PostgreSQL when you’re trying to create a sequence, it’s probably because your sequence’s maximum possible value is lower than the start value.
To fix this issue, change either the start value or maximum value so that the maximum value is greater than the start value.
Continue readingIf you’re getting an error that reads something like “nextval: reached maximum value of sequence “sequence1” (3)” in PostgreSQL, it’s probably because you’re trying to generate a new value from a sequence, but the sequence has already reached its maximum value.
We have quite a few options when it comes to dealing with this issue.
Continue reading