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Blacknest BDS Schema Overview

Date 2008-04-04
Version 0.2

Note that this is a "work in progress" document and is being continually updated.

Introduction

This document provides an overview of the Blacknest Data System (BDS) Database Schema.

Database Schema Overview

The BDS Database holds information on all of the Seismic data and associated metadata. The database will be implemented as a MySQL database. Generally the database is not directly accessed. It is normally only accessed by the BDS Data Engine in response to API requests.

General

  • Dates and times: These need to be stored to the nearest ms. We could use a MySQL DateTime + an Integer for the ms. Or we could simply use a String formated using ISO 8601 format: eg "2002-04-03T11:20:53.103". An entry of 000-00-00T00:00:00.000 is used for unknown. (The Postgress DateTime field has millisecond accuracy and MySQL may be extended to support it in the future. Updating from a String to a millisecond accurate DateTime field would be easy in the future).

Overall Management

Groups

The list of user groups.
Name Type Attributes Description
id String primary, auto_increment Unique ID for this entry
group String primary The Group name
description String The Groups description
permissions String Comma separated list of permissions (or separate table)
Permissions based on Network/(Station/Array)/Period

Users

The list of users.
Name Type Attributes Description
id Integer primary, auto_increment Unique ID for this entry. (Used as the userId)
loginId String primary The users login ID
loginPassword String The users login password (Encrypted)
name String The users full name
emailAddress String The users email address
telephone String The users telephone number
enabled Bool If this user is enabled

UserGroups

Used to keep the list of groups a user belongs to.
Name Type Attributes Description
id Integer primary, auto_increment Unique ID for this entry. (Used as the userId)
userId Integer primary The userId for this group
group String A group this user belongs to

Overall Information MetaData

I suggest that all the tables have a "date when last altered" column that is automatically updated when the row is modified. TB: We could use a separate Changes table to handle this.

Networks

The list of networks.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
network String Primary The Network name
description String The Network description

NetworkStations

Used to keep the list of all stations managed by a network.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
network String Primary The Network name
station String The Station/Array name

Stations

Used to keep the list of all station names. If a station is only managed by one network then we could integrate the NetworkStations table with this one.
How do we denote stations that are both an array and a co-located three-component set? Will we want to do searches for three-component sets that include those co-located with an array? At present our co-located three-component set has a different name (EKB) from the array (EKA), but will this change after the upgrade? We could have duplicate entries, one to denote the array, one for the three-component set, but we will not be able to use "station" as a primary key if it is not unique within the table. Also, is this table going to contain all the pits within an array? Will they have a different station type from an isolated single station? (they don't in IDC table "site" - array pits are all designated "ss" - "single station")
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
station String
The Station/Array name
type String The station type (Station, Array, Pit)
array String The array this station/pit belongs to if in an array

Channel MetaData

StationLocations

Used to keep the list of all station locations
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
datum String The Datum for the Latitude/Longitude normally WGS84
latitude Double The Latitude in degrees using the datum.
longitude Double The Longitude in degrees using the datum.
elevation Double The ground level elevation in metres from the WGS84 ellipsoid (Sea level)
arrayOffsetEast Double For a station in an array, this is the offset from the array's centre in km
arrayOffsetNorth Double For a station in an array, this is the offset from the array's centre in km

Channels

Used to keep the list of all channels.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time for this channel
endTime String Primary The End time for this channel
network String Primary The Network name
station String Primary The Station/Array name
channel String The Channels primary identifier (Usually the channelType and channelAux combined)
channelType String The Channels Type. Three characters such as (BHZ)
channelAux String The Channels Auxiliary identifier. Could be the location ID (Usually two digits, e.g. "01")

Calibrations

Used to keep the list of all calibration entries for a channel.
Name Type The location ID (see Sensor Locations, above)Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time for this channel
endTime String Primary The End time for this channel
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
calibrationFrequency Double The frequency that the CalibrationFactor value is valid for (Hz)
calibrationFactor Double The scaling value to apply to the data to normalise to nanometres. This is a measured value at the calibration frequency. For seisometers it is in nanometres/count. The calibrationUnits specify the actual units.
calibrationUnits String Unit for calibration Factor, e.g. volts per (m/s), volts per Pa

Instruments

Used to keep the list of all instruments for a channel. Note there not be an instrument entry for a channel if there are separate digitiser and sensor units.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
instrument String The instrument name
type String The type of instrument - e.g. seismometer, infrasound microphone, hydrophone, wind gauge, thermometer .
model String The instrument model name. The Vendor make/type of instrument. Only used when there is a unique physical instrument
serialNumber String The instrument's serial number. Only used when there is a unique physical instrument.

Digitisers

Used to keep the list of all digitisers for a channel.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
digitiser String The digitiser's model name
type String The digitiser type. Only used when there is a unique physical digitiser
model String The digitiser's model name. Only used when there is a unique physical digitiser
serialNumber String The digitisers's serial number. Only used when there is a unique physical digitiser
samplingFrequency Double The sampling frequency (Hz)
initialSamplingFrequency Double The initial pre-decimation sampling frequency (Hz)
gain Double The overall gain of the digitiser at the manufacturers calibration frequency (counts/volt?). (For information only)

Sensors

Used to keep the list of all sensors for a given channels digitiser.
I don't understand this table. As it stands it is a duplicate of "instrument" above. If it is meant to be keeping track of the several channels served by a single digitiser, then it has a "many-to-one" relationship with individual rows of the "digitiser" table (i.e. one digitiser has many sensors). Hence it should have as foreign key the digitiser model and serial number. The "digitiser" table above should not contain a "channel" row if each digitiser is taken to serve many channels.
TB: The sensor is separate from an instrument. An instrument consists of a set of digitisers + sensors. In some cases there is no instrument, a channel has a physically separate digitiser and set of sensors. In some cases there is just a physical instrument that has internally a digitiser and set of sensors. For channels that do not have a separately identifiable sensor there would be no Sensor table entries.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
sensor String The sensor name.
type String The type of sensor. (Seismometer, Hydrophone etc)
model String The sensor's model name. Only used when there is a unique physical sensor
serialNumber String The sensor's serial number. Only used when there is a unique physical sensor
gain Double The overall gain of the sensor at the manufacturers calibration frequency. (For information only)
gainUnits String Units in which gain is quoted, e.g. volts per (m/s), volts per Pa

SensorLocations

Used to keep the list of sensor locations. The placement angles could be in a separate table.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
sensor String The sensor name
depth Double The depth below ground level (m)
verticalAngle Double The Sensor's placement vertical angle in degrees degrees with zero = vertically up (degrees)
horizontalAngle Double The Sensor's placement horizontal angle in degrees clockwise from north (degrees)

Responses

Used to keep the list of all frequency responses for a given channels digitiser and sensors. We may need sensor id/name and digitiser id/name in here.
Name Type Attributes Description
id Integer not_null, auto_increment Unique ID for this entry
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network name
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
digitiser String The digitiser name (may be null if this is a sensor response)
sensor String The sensors name (may be null if this is a digitiser response)
response String The responses name (Sensor,Anti-Aliasing filter, Digitiser, post filter etc)
type String The type of response (PoleZero,AmplitudePhase or FIR Coefficients)
data Blob PoleZero, AmplitudePhase or FIR Coefficient data
gain Double Overall gain at gain frequency. (For information)
gainFrequency Double Frequency that gain is valid for. (For information)
decimation Double Decimation performed post filter. (For information)
symmetry String Symmetry for FIR coefficients (A = asymmetric, B = symmetric[odd], C = symmetric[even])


Seismic Data

Data

Used to keep the list of data files managed by the BDS.

We may need to add "channel" and "channelAux" to the primary keys if we want to store data in non multiplexed, individual channel files.

Name Type Attributes Description
id Integer auto_increment,Primary Unique integer ID
startTime String Primary The Start time
endTime String Primary The End time
network String Primary The Network organisation the original data is from
station String Primary The Station/Array name
source String Primary Some information on the source of this data (DIRECT, TAPE, PROCESSED ...). This would allow multiple sources of data from the same Array and TimePeriod. It could also support processed data. 
location String The location of the data. This could be a local archive or even a remote archive
format String The data's format
url String File location. This can embody a protocol, host, path and filename.
comment String A general comment string.
channels String A list of (stations/pits)/channels some how ....

Misc Data

Notes

Used to keep the list of data outages and other notes.
Name Type Attributes Description
id Integer auto_increment,Primary Unique integer ID
startTime String Primary The Start time
endTime String Primary The End time
network String The Network organisation the original data is from
station String Primary The Station/Array name
channel String Primary The Channels primary identifier
type String The entry type: (Outage, Note, Warning etc)
source String The source of the note
title String A Title for the note
comment String A Comment for the note

Changes

Used to keep the list of changes made to the database. Not sure on this.
Name Type Attributes Description
id Integer auto_increment,Primary Unique integer ID
time String The time the change was made
table String The Table that was altered. (Should be have a list of tables ?)
id Integer The tables entry that was altered (We would need a unique ID in each record for this)(Should this be in effect a list ?)
user String The User that made the change
title String A Title for the change
comment String A Comment for the change

We will also need database information store on the following:
  • Data Request queues
  • Data Requests serviced
  • Data additions made ?

Notes