Corpus 0.2.0: 35 scenarios (github.com/AndreaBozzo/tabular-evolution-corpus@cf6599a, tag v0.2.0)
62472e3 verified | license: apache-2.0 | |
| pretty_name: Tabular Evolution Corpus | |
| size_categories: | |
| - n<1K | |
| tags: | |
| - schema-evolution | |
| - parquet | |
| - arrow | |
| - data-engineering | |
| - test-fixtures | |
| - tabular | |
| configs: | |
| - config_name: default | |
| default: true | |
| data_files: | |
| - split: scenarios | |
| path: data/scenarios.parquet | |
| # Tabular Evolution Corpus | |
| > Source, generator and validator: | |
| > [github.com/AndreaBozzo/tabular-evolution-corpus](https://github.com/AndreaBozzo/tabular-evolution-corpus). | |
| > This card is the `README.md` of the Hugging Face dataset repository; the | |
| > GitHub repository keeps its own README. | |
| A small, deterministic corpus of Parquet datasets that change over time. Each | |
| **scenario** is one logical dataset at two or more versions, with a manifest | |
| that records **what structurally changed** and **which row and value facts | |
| hold** across each transition. Every fact is verified against the files. | |
| The corpus records facts, not compatibility verdicts. Whether a change is | |
| acceptable is for the engine, table format or data contract under test to | |
| decide. | |
| ## What the viewer shows | |
| The viewer shows the **catalog**, `data/scenarios.parquet`, with one row per | |
| scenario (35 rows). The catalog is an index. The versioned fixture files it | |
| points to live in the same repository under `fixtures/<scenario_id>/` | |
| (`v0.parquet`, `v1.parquet`, ..., `scenario.json`). | |
| The `configs` block above deliberately restricts the viewer and | |
| `load_dataset` to the catalog. The fixture Parquet files have a different | |
| schema in every scenario and are **not** rows of one dataset. Without the | |
| explicit config, automatic data-file detection would try to load them as one. | |
| ## Catalog columns | |
| | column | type | meaning | | |
| | --- | --- | --- | | |
| | `scenario_id` | string | stable identifier; also the fixture directory name | | |
| | `title`, `description` | string | what changes, stated as facts | | |
| | `category` | string | additive, subtractive, numeric, nullability, representation, structural, temporal, edge | | |
| | `notes` | list<string> | caveats, e.g. differences that exist only in the stored Arrow schema | | |
| | `tags` | list<string> | free-form, kebab-case | | |
| | `row_identity` | list<string> | columns that identify a row in every version; empty means rows are identified by position | | |
| | `version_count`, `version_ids`, `row_counts` | int64, list<string>, list<int64> | versions in order | | |
| | `mutation_count`, `mutation_kinds` | int64, list<string> | structural changes across all transitions | | |
| | `paths` | list<string> | field paths touched by a mutation or a value change | | |
| | `value_change_relations` | list<string> | how changed values relate (`nearest_float64`, `utf8_encoded`, ...) | | |
| | `schema_changed`, `values_changed`, `parquet_schema_changed` | bool | quick filters | | |
| | `base_file`, `final_file`, `manifest_path` | string | repository-relative paths | | |
| | `base_schema_json`, `final_schema_json`, `transitions_json` | string | JSON; full detail is in `scenario.json` | | |
| | `base_fingerprint`, `final_fingerprint` | string | logical fingerprints (schema + values + row order) | | |
| Nested manifest structures are JSON strings because their shape depends on the | |
| mutation kind. Every other column is a scalar or a list of scalars. | |
| ## Usage | |
| ```python | |
| from datasets import load_dataset | |
| catalog = load_dataset("AndreaBozzo/tabular-evolution-corpus", split="scenarios") | |
| ``` | |
| To get the fixtures, download the repository files: | |
| ```python | |
| from huggingface_hub import snapshot_download | |
| root = snapshot_download("AndreaBozzo/tabular-evolution-corpus", repo_type="dataset") | |
| # root/fixtures/<scenario_id>/{v0.parquet, v1.parquet, scenario.json} | |
| ``` | |
| Every corpus release is a tag, both here and on GitHub. Pass | |
| `revision="v0.2.0"` to either call to get exactly that release. A released tag | |
| is never moved, and a changed corpus gets a new release. | |
| ```sql | |
| -- DuckDB | |
| SELECT scenario_id, mutation_kinds, row_counts | |
| FROM read_parquet('hf://datasets/AndreaBozzo/tabular-evolution-corpus/data/scenarios.parquet') | |
| WHERE category = 'numeric'; | |
| ``` | |
| ## Dataset structure | |
| ```text | |
| data/scenarios.parquet catalog (this viewer) | |
| fixtures/<scenario_id>/ one directory per scenario | |
| v0.parquet, v1.parquet ... versions, 0-8 rows each | |
| scenario.json manifest (JSON Schema: schema/scenario.schema.json) | |
| schema/scenario.schema.json | |
| SHA256SUMS | |
| ``` | |
| ## Creation | |
| All data is synthetic, written by the generator in the source repository with | |
| a pinned PyArrow Parquet writer (uncompressed, format 2.6, one row group). | |
| Values are chosen to expose boundaries: NaN, infinities, `-0.0`, 2^53 + 1, | |
| int and decimal extremes, composed vs decomposed Unicode, empty strings, | |
| nested nulls, pre-epoch timestamps, timestamps at both ends of the | |
| nanosecond range. Regeneration is logically reproducible, | |
| and byte-reproducible with the same PyArrow version. | |
| ## Intended use and limitations | |
| Intended as test input for ingestion frameworks, dataframe libraries, query | |
| engines, lakehouse tooling, schema registries, contract validators and | |
| profilers. It is not training data, not a performance benchmark, and not a | |
| conformance suite for Arrow or Parquet (see apache/parquet-testing and the | |
| Arrow integration tests for those). Corpus 0.2.0 covers Parquet only and 35 | |
| scenarios. Nested evolution covers structs, lists and maps; datasets are | |
| keyed or identified by row position. | |
| **One writer.** Every file is written by a single pinned Parquet writer | |
| (PyArrow / Arrow C++, recorded in each file's `created_by`). The scenarios | |
| vary the data, not the writer. Differences that exist only in the Arrow schema | |
| stored in the file (`large_string`, dictionary encoding) are flagged in each | |
| manifest, because readers that ignore that schema see no change. Fixtures | |
| from other writers are planned but not included. | |
| ## License | |
| Apache-2.0. No personal data: every name, address and e-mail in the fixtures | |
| is invented or a well-known public name used as a placeholder. | |