Table: `ndb.variables`#

Description#

This table lists Variables, which always consist of a Taxon and Units of measurement. Variables can also have Elements, Contexts, and Modifications. Thus, the same taxon with different measurement units (e.g. present/absent, NISP, MNI) are different Variables.

TODO: Expand this description with: - What data does this table store? - What is the business/research purpose? - How is this data collected or generated? - Are there any important caveats or data quality issues?

Table Structure#

Schema: ndb | Table Comment: This table lists Variables, which always consist of a Taxon and Units of measurement. Variables can also have Elements, Contexts, and Modifications. Thus, the same taxon with different measurement units (e.g. present/absent, NISP, MNI) are different Variables.

Statistics#

Metric	Value
Row Count	57,198
Total Size	18 MB
Table Size	4368 kB
Indexes Size	13 MB

Relationships#

Primary Key: variableid

Foreign Keys:

taxonid → taxa.taxonid
variablecontextid → variablecontexts.variablecontextid
variableelementid → variableelements.variableelementid
variableunitsid → variableunits.variableunitsid

Referenced By:

TODO: Document which tables reference this table (will be auto-detected in validation).

Data Dictionary#

Column	Type	Nullable	Default	Constraints	Description
`variableid`	integer	✗	`nextval('ndb.seq_variables_...`	PRIMARY KEY	An arbitrary Variable identification number.
`taxonid`	integer	✗	`-`	FOREIGN KEY, UNIQUE	Taxon identification number. Field links to the Taxa table.
`variableelementid`	integer	✓	`-`	FOREIGN KEY, UNIQUE	Variable Element identification number. Field links to the VariableElements lookup table.
`variableunitsid`	integer	✓	`-`	FOREIGN KEY, UNIQUE	Variable Units identification number. Field links to the VariableUnits lookup table.
`variablecontextid`	integer	✓	`-`	FOREIGN KEY, UNIQUE	Variable Context identification number. Field links to the VariableContexts lookup table.
`recdatecreated`	timestamp without time zone	✗	`timezone('UTC'::text, now())`	-
`recdatemodified`	timestamp without time zone	✗	`-`	-

TODO: Review column descriptions and add comments where missing.

Usage Examples#

Example 1: Basic Selection#

-- Get recent records from variables
SELECT *
FROM variables
ORDER BY variableid DESC
LIMIT 10;

Purpose: Retrieve the 10 most recent records from variables

Example 2: Count Records#

-- Count total records
SELECT COUNT(*) as total_records
FROM variables;

Purpose: Get the total number of records in variables

Example 3: Filter by Date Range#

-- Get records within a date range
SELECT *
FROM variables
WHERE recdatecreated >= '2024-01-01'
  AND recdatecreated < '2025-01-01'
ORDER BY recdatecreated DESC;

Purpose: Retrieve records from variables within a specific date range

Example 4: Join with taxa#

-- Join with related table
SELECT 
    t1.*,
    t2.*
FROM variables t1
INNER JOIN taxa t2 
    ON t1.taxonid = t2.taxonid
LIMIT 100;

Purpose: Retrieve variables records with related data from taxa

Example 5: Aggregate Data#

-- Aggregate records by taxonid
SELECT 
    taxonid,
    COUNT(*) as count
FROM variables
GROUP BY taxonid
ORDER BY count DESC
LIMIT 10;

Purpose: Count records grouped by taxonid

TODO: Add more specific examples relevant to common research questions or operational tasks.

Data Quality Notes#

Automated Data Quality Tests#

This table is subject to the following automated quality checks:

❌ valid_003: valid_terminal_taxa_have_values

Severity: WARNING
Status: FAILED
Description: Taxa that are identified as 'leaves' in the database should be associated with values in the database.
Suggested Remediation: - Check with data stewards for the particular data type.
Ensure that the taxa are valid.

See the Data Quality Report for details.

Maintenance#

Data Owner: TODO: Assign owner
Update Frequency: TODO: Document frequency
Last Major Schema Change: TODO: Document when schema last changed

Table: ndb.variables#