Table: `ndb.sampleages`#

Description#

This table stores sample ages. Ages are assigned to a Chronology. Because there may be more than one Chronology for a Collection Unit, samples may be assigned different ages for different Chronologies. A simple example is one sample age in radiocarbon years and another in calibrated radiocarbon years. The age units are an attribute of the Chronology.

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 stores sample ages. Ages are assigned to a Chronology. Because there may be more than one Chronology for a Collection Unit, samples may be assigned different ages for different Chronologies. A simple example is one sample age in radiocarbon years and another in calibrated radiocarbon years. The age units are an attribute of the Chronology.

Statistics#

Metric	Value
Row Count	950,838
Total Size	383 MB
Table Size	76 MB
Indexes Size	307 MB

Relationships#

Primary Key: sampleageid

Foreign Keys:

chronologyid → chronologies.chronologyid
sampleid → samples.sampleid

Referenced By:

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

Data Dictionary#

Column	Type	Nullable	Default	Constraints	Description
`sampleageid`	integer	✗	`nextval('ndb.seq_sampleages...`	PRIMARY KEY	An arbitrary Sample Age identification number.
`sampleid`	integer	✗	`-`	FOREIGN KEY	Sample identification number. Field links to the Samples table.
`chronologyid`	integer	✗	`-`	FOREIGN KEY	Chronology identification number. Field links to the Chronologies table.
`age`	double precision	✓	`-`	-	Age of the sample
`ageyounger`	double precision	✓	`-`	-	Younger error estimate of the age. The definition of this estimate is an attribute of the Chronology. Many ages do not have explicit error estimates assigned.
`ageolder`	double precision	✓	`-`	-	Older error estimate of the age.
`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 sampleages
SELECT *
FROM sampleages
ORDER BY sampleageid DESC
LIMIT 10;

Purpose: Retrieve the 10 most recent records from sampleages

Example 2: Count Records#

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

Purpose: Get the total number of records in sampleages

Example 3: Filter by Date Range#

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

Purpose: Retrieve records from sampleages within a specific date range

Example 4: Join with chronologies#

-- Join with related table
SELECT 
    t1.*,
    t2.*
FROM sampleages t1
INNER JOIN chronologies t2 
    ON t1.chronologyid = t2.chronologyid
LIMIT 100;

Purpose: Retrieve sampleages records with related data from chronologies

Example 5: Aggregate Data#

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

Purpose: Count records grouped by sampleid

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:

✅ comp_004: sample_ages_for_samples

Severity: WARNING
Status: PASSED
Description: Samples should have sample ages, whether from a chronology or collection date.

❌ valid_005: sample_ages_scaled_properly

Severity: ERROR
Status: FAILED
Description: Sample ages and chronologies should have ages that have the correct age range. younger ages should always be more recent than older ages.
Suggested Remediation: - Likely we just need to flip the ages around from younger to older.
The chronology may also need some examination.

✅ biz_001: modern_samples_have_recent_dates

Severity: WARNING
Status: PASSED
Description: Samples marked as modern should have dates after 1950

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.sampleages#