Difference between revisions of "Database structure"
From PhotoVoltaic Logger new generation
m (→pvlng_reading_num / pvlng_reading_str) |
m (→pvlng_reading_num / pvlng_reading_str) |
||
| Line 22: | Line 22: | ||
[[File:DBTableReadingNum.png]] [[File:DBTableReadingStr.png]] | [[File:DBTableReadingNum.png]] [[File:DBTableReadingStr.png]] | ||
| + | |||
| + | The difference between the reading tables is only the data format for reading values. | ||
The timestamps are '''not''' stored as "normal" timestamp type, but as '''unsigned integer'''. | The timestamps are '''not''' stored as "normal" timestamp type, but as '''unsigned integer'''. | ||
It was tested and have significant more performance for consolidated data readouts. | It was tested and have significant more performance for consolidated data readouts. | ||
Revision as of 16:34, 2 March 2014
Contents
Abstract
pvlng_type
pvlng_channel
pvlng_tree
The channel tree is organized in a nested set structure.
The nested set model is a particular technique for representing nested sets (also known as trees or hierarchies) in relational databases. -- Wikipedia:Nested set model
More theory about nested sets.
pvlng_reading_num / pvlng_reading_str
The difference between the reading tables is only the data format for reading values.
The timestamps are not stored as "normal" timestamp type, but as unsigned integer.
It was tested and have significant more performance for consolidated data readouts.
