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For example, a table of 128 rows with a Boolean column requires 128 bytes a row-oriented format (one byte per Boolean) but 128 bits (16 bytes) in a column-oriented format (via a bitmap). Another example is the use of run-length encoding to encode a column.
Note (1): The users need to use a function from freeAdhocUDF library or similar. [121] Note (2): Can be implemented for most data types using expression-based indexes. Note (3): Can be emulated by indexing a computed column [122] (doesn't easily update) or by using an "Indexed View" [123] (proper name not just any view works [124]).
Run-length encoding (RLE) is a form of lossless data compression in which runs of data (consecutive occurrences of the same data value) are stored as a single occurrence of that data value and a count of its consecutive occurrences, rather than as the original run. As an imaginary example of the concept, when encoding an image built up from ...
A variable-length quantity (VLQ) is a universal code that uses an arbitrary number of binary octets (eight-bit bytes) to represent an arbitrarily large integer. A VLQ is essentially a base-128 representation of an unsigned integer with the addition of the eighth bit to mark continuation of bytes.
A column family is a database object that contains columns of related data. It is a tuple (pair) that consists of a key–value pair , where the key is mapped to a value that is a set of columns. In analogy with relational databases, a column family is as a "table", each key-value pair being a "row".
Golomb coding is a lossless data compression method using a family of data compression codes invented by Solomon W. Golomb in the 1960s. Alphabets following a geometric distribution will have a Golomb code as an optimal prefix code, [1] making Golomb coding highly suitable for situations in which the occurrence of small values in the input stream is significantly more likely than large values.
Example of a USA/UK CSV file (where the decimal separator is a period/full stop and the value separator is a comma): Year,Make,Model,Length 1997,Ford,E350,2.35 2000,Mercury,Cougar,2.38 Example of an analogous European CSV/DSV file (where the decimal separator is a comma and the value separator is a semicolon):
Example: The linear block code with the following generator matrix is a [,,] Hadamard code: = ( ). Hadamard code is a special case of Reed–Muller code . If we take the first column (the all-zero column) out from G H a d {\displaystyle {\boldsymbol {G}}_{\mathrm {Had} }} , we get [ 7 , 3 , 4 ] 2 {\displaystyle [7,3,4]_{2}} simplex code , which ...