MySQL 8.0.39
Source Code Documentation
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Following is a list of the terms used in the TempTable storage engine source code.
This is to avoid confusion because in the surrounding code (outside of storage/temptable) different terms are used to designate the one thing and in some cases a given term can designate different things.
For example some surrounding code reads key->records_per_key(j)
where the first "key" (key->...
) designates an index and the second "key" (..._key(j)
) designates distinct indexed cells.
Below are the terms used in TempTable source code with some explanations.
A table consists of rows and columns.
id | color_name | hex_code |
---|---|---|
1 | Red | FF0000 |
2 | Orange | FF8800 |
3 | Yellow | FFFF00 |
4 | Green | 00FF00 |
5 | Cyan | 00FFFF |
6 | Blue | 0000FF |
7 | Pink | FF00FF |
A row is a horizontal slice from the table.
id | color_name | hex_code |
---|---|---|
1 | Red | FF0000 |
2 | Orange | FF8800 |
3 | Yellow | FFFF00 |
4 | Green | 00FF00 |
5 | Cyan | 00FFFF |
6 | Blue | 0000FF |
7 | Pink | FF00FF |
Also called "record" elsewhere.
A column is a vertical slice from the table. It has a name - "hex_code" in the example.
id | color_name | hex_code |
---|---|---|
1 | Red | FF0000 |
2 | Orange | FF8800 |
3 | Yellow | FFFF00 |
4 | Green | 00FF00 |
5 | Cyan | 00FFFF |
6 | Blue | 0000FF |
7 | Pink | FF00FF |
Also called "field" elsewhere.
A cell is where a row intersects with a column.
id | color_name | hex_code |
---|---|---|
1 | Red | FF0000 |
2 | Orange | FF8800 |
3 | Yellow | FFFF00 |
4 | Green | 00FF00 |
5 | Cyan | 00FFFF |
6 | Blue | 0000FF |
7 | Pink | FF00FF |
Also called "field" elsewhere.
An index is a complex structure covering one or more columns. Also called "key" elsewhere.
A column that is covered by an index.
An indexed cell is a cell that is covered by an index. An intersection between a row and an indexed column. Also called "key", "field", "subkey", "key part", "key segment" elsewhere.