Sherlock is a deep-learning approach to semantic data type detection, i.e. labeling tables with column types such as name, address, etc. This is helpful for, among others, data validation, processing and integration. This repository provides data and code to guide usage of Sherlock, retraining the model, and replication of results. Visit https://sherlock.media.mit.edu for more background on this project.

1. You can install Sherlock by cloning this repository, and run pip install ..
2. Install dependencies using pip install -r requirements.txt (or requirements38.txt depending on your Python version).

The 00-use-sherlock-out-of-the-box.ipynb notebook demonstrates usage of the readily trained model for a given table.

The notebooks in notebooks/ prefixed with 01-data processing.ipynb and 02-1-train-and-test-sherlock.ipynb can be used to reproduce the results, and demonstrate the usage of Sherlock (from data preprocessing to model training and evaluation).

The raw data (corresponding to annotated table columns) can be downloaded using the download_data() function in the helpers module. This will download /- 500MB of data into the data directory. Use the 01-data-preprocessing.ipynb notebook to preprocess this data. Each column is then represented by a feature vector of dimensions 1x1588. The extracted features per column are based on "paragraph" embeddings (full column), word embeddings (aggregated from each column cell), character count statistics (e.g. average number of "." in a column's cells) and column-level statistics (e.g. column entropy).

The SherlockModel class is specified in the sherlock.deploy.model module. This model constitutes a multi-input neural network which specifies a separate network for each feature set (e.g. the word embedding features), concatenates them, and finally adds a few shared layers. Interaction with the model follows the scikit-learn interface, with methods fit, predict and predict_proba.

The originally trained SherlockModel can be used for generating predictions for a dataset. First, extract features using the features.preprocessing module. The original weights of Sherlock are provided in the repository in the model_files directory and can be loaded using the initialize_model_from_json method of the model. The procedure for making predictions (on the data) is demonstrated in the 02-1-train-and-test-sherlock.ipynb notebook.

The notebook 02-1-train-and-test-sherlock.ipynb also illustrates how Sherlock can be retrained. The model will infer the number of unique classes from the training labels unless you load a model from a json file, the number of classes will be 78 in that case.

To cite this work, please use the below bibtex:

@inproceedings{Hulsebos:2019:SDL:3292500.3330993,
 author = {Hulsebos, Madelon and Hu, Kevin and Bakker, Michiel and Zgraggen, Emanuel and Satyanarayan, Arvind and Kraska, Tim and Demiralp, {\c{C}}a{\u{g}}atay and Hidalgo, C{\'e}sar},
 title = {Sherlock: A Deep Learning Approach to Semantic Data Type Detection},
 booktitle = {Proceedings of the 25th ACM SIGKDD International Conference on Knowledge Discovery \&\#38; Data Mining},
 year={2019},
 publisher = {ACM},
}

├── data   <- Placeholder directory to download data into.

├── docs   <- Files for https://sherlock.media.mit.edu landing page.

├── model_files  <- Files with trained model weights and specification.
    ├── sherlock_model.json
    └── sherlock_weights.h5

├── notebooks   <- Notebooks demonstrating data preprocessing and train/test of Sherlock.
    └── 00-use-sherlock-out-of-the-box.ipynb
    └── 01-data-preprocessing.ipynb
    └── 02-1-train-and-test-sherlock.ipynb
    └── 02-2-train-and-test-sherlock-rf-ensemble.ipynb
    └── 03-train-paragraph-vector-features-optional.ipynb

├── sherlock  <- Package.
    ├── deploy  <- Code for (re)training Sherlock, as well as model specification.
        └── helpers.py
        └── model.py
    ├── features     <- Files to turn raw data, storing raw data columns, into features.
        ├── feature_column_identifiers   <- Directory with feature names categorized by feature set.
        └── bag_of_characters.py
        └── bag_of_words.py
        └── par_vec_trained_400.pkl
        └── paragraph_vectors.py
        └── preprocessing.py
        └── word_embeddings.py
    ├── helpers.py     <- Supportive modules.