SQLITE_INTEGER value bytes

Question

I have a question about the data types in sqlite3.

As a value of SQLITE_INTEGER can be stored in 1, 2, 3, 4, 6, or 8 bytes depending on the magnitude of the value, if I only know that a column in SQlite database stores SQLITE_INTEGER, how can I know a value in this column is 4 bytes or 6-8 bytes integer, or which one should be used to get the value, sqlite3_column_int() or sqlite3_column_int64()?

Can I use sqlite3_column_bytes() in this case? but according to the documentation, sqlite3_column_bytes() is primarily used for TEXT or BLOB.

Thanks!

CL. · Accepted Answer · 2012-12-12 07:55:50Z

2

When SQLite steps into a record, all integer values are expanded to 64 bits.
sqlite3_column_int() returns the lower 32 bits of that value without checking for overflows.

When you call sqlite3_column_bytes(), SQLite will convert the value to text, and return the number of characters.

You cannot know how large an integer value is before reading it. Afterwards, you can check the list in the record format documentation for the smallest possible format for that value, but if you want to be sure that integer values are never truncated to 32 bits, you have to always use sqlite3_column_int64(), or ensure that large values get never written to the DB in the first place (if that is possible).

answered Dec 12, 2012 at 7:55

CL.

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1 Comment

Lewis Over a year ago

Thanks! So I guess I have to get the value by sqlite3_column_int64() first, and then truncate it to 32bit if it is in the range of a 32bit value. Any other methods?

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