Bit strings are strings of 1's and 0's. They can be used to store bit masks.
DWS supports two SQL bit types: bit(n) and bit varying(n), where n is a positive integer.
The bit type data must match the length n exactly. It is an error to attempt to store shorter or longer bit strings. The 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.
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.
-- Create a table. CREATE TABLE bit_type_t1 ( BT_COL1 INTEGER, BT_COL2 BIT(3), BT_COL3 BIT VARYING(5) ) DISTRIBUTE BY REPLICATION; -- Insert data. INSERT INTO bit_type_t1 VALUES(1, B'101', B'00'); -- Specify the type length. An error is reported if an inserted string exceeds this length. INSERT INTO bit_type_t1 VALUES(2, B'10', B'101'); ERROR: bit string length 2 does not match type bit(3) CONTEXT: referenced column: bt_col2 -- Specify the type length. Data is converted if it exceeds this length. INSERT INTO bit_type_t1 VALUES(2, B'10'::bit(3), B'101'); -- View data. SELECT * FROM bit_type_t1; bt_col1 | bt_col2 | bt_col3 ---------+---------+--------- 1 | 101 | 00 2 | 100 | 101 (2 rows) -- Delete the table. DROP TABLE bit_type_t1;