Bit strings are strings of 1's and 0's. They can be used to store or visualize bit masks. There are two SQL bit types: BIT(n) and BIT VARYING(n), where n is a positive integer.
BIT type data must match the length n exactly; it is an error to attempt to store shorter or longer bit strings. BIT VARYING data is of variable length up to the maximum length n; longer strings will be rejected. Writing BIT without a length is equivalent to BIT(1), while BIT VARYING without a length specification means unlimited length.
Note: If one explicitly casts a bit-string value to BIT(n), it will be truncated or zero-padded on the right to be exactly n bits, without raising an error. Similarly, if one explicitly casts a bit-string value to BIT VARYING(n), it will be truncated on the right if it is more than n bits.
Note: Prior to PostgreSQL 7.2, BIT data was always silently truncated or zero-padded on the right, with or without an explicit cast. This was changed to comply with the SQL standard.
Refer to Section 1.1.2.2 for information about the syntax of bit string constants. Bit-logical operators and string manipulation functions are available; see Chapter 6.
Example 5-3. Using the bit string types
CREATE TABLE test (a BIT(3), b BIT VARYING(5)); INSERT INTO test VALUES (B'101', B'00'); INSERT INTO test VALUES (B'10', B'101'); ERROR: Bit string length 2 does not match type BIT(3) INSERT INTO test VALUES (B'10'::bit(3), B'101'); SELECT * FROM test; a | b -----+----- 101 | 00 100 | 101
No comments could be found for this page.
Please use this form to add your own comments regarding your experience with particular features of PostgreSQL, clarifications of the documentation, or hints for other users. Please note, this is not a support forum, and your IP address will be logged. If you have a question or need help, please see the faq, try a mailing list, or join us on IRC. Note that submissions containing URLs or other keywords commonly found in 'spam' comments may be silently discarded. Please contact the webmaster if you think this is happening to you in error.
In order to submit a comment, you must have a community account.
* denotes required field