Embodiments associate a relevant semantic data type (e.g., date) with incoming raw data (e.g., a column of digits) which lacks metadata. Assignment of semantic data type is inferred from a plurality of features. A first step determines a first feature comprising success rate in converting the raw data into various semantic data types. Then, alignment between observed/reference distributions of other features (e.g., data first digit, data length) is determined per-semantic data type. Total scores for each semantic data type are calculated from the combined features, and used as a basis for ranking the semantic data types. The total scores may reflect a weighting of the various features. In a second step, top-ranked semantic data types may be further differentiated from one another by applying additional features. User feedback regarding accuracy of semantic data type assignment, may be incorporated into training data used to modify the feature reference distributions.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A computer-implemented method comprising: receiving a plurality of data points lacking associated metadata; determining a first score of a first feature comprising a success rate converting the plurality of data points to a semantic data type; determining a second score from alignment between an observed distribution of a second feature in the plurality of data points, and a reference distribution of the second feature in the semantic data type; determining a third score from alignment between an observed distribution of a third feature in the plurality of data points, and a reference distribution of the third feature in the semantic data type; calculating a total score for the semantic data type from the first, second, and third scores; determining an initial ranking of the total score in comparison with another total score reflecting the first, second, and third features in another semantic data type; identifying a fourth feature differentiating between the semantic data type and the other semantic data type; assigning a final ranking to the total score and the other total score by, determining alignment between an observed distribution of the fourth feature in the plurality of data points, and reference distributions of the fourth feature in the semantic data type and in the other semantic data type; assigning the semantic data type to the plurality of data points based upon the final ranking; and storing the plurality of data points with metadata indicating the semantic data type. 2. A method as in claim 1 wherein: the alignment between the observed distribution of the second feature and the reference distribution of the second feature is reflected by a Kolmogorov-Smirnov distance. 3. A method as in claim 1 wherein the second feature comprises a data point length. 4. A method as in claim 1 wherein the second feature comprises a data point first digit. 5. A method as in claim 1 wherein the fourth feature comprises a number of digits behind a decimal point. 6. A method as in claim 1 wherein the fourth feature comprises a data point digit other than a first digit. 7. A method as in claim 1 further comprising: deriving the reference distribution of the second feature from training data; receiving feedback regarding accuracy of the assignment of semantic data type; and updating the training data to reflect the feedback. 8. A method as in claim 1 further comprising: receiving feedback regarding accuracy of the assignment of semantic data type; calculating the total score by assigning respective weight coefficients to the first, second, and third scores; and updating the respective weight coefficients based upon the feedback. 9. A method as in claim 1 wherein converting the plurality of data points to the semantic data type employs a pattern matching mechanism comprising regular expressions specifying class-specific search patterns. 10. A non-transitory computer readable storage medium embodying a computer program for performing a method, said method comprising: receiving a plurality of data points lacking associated metadata; determining a first score of a first feature comprising a success rate converting the plurality of data points to a semantic data type; determining a second score from alignment between an observed distribution of a second feature in the plurality of data points, and a reference distribution of the second feature in the semantic data type, the alignment comprising a Kolmogorov-Smirnov distance; determining a third score from alignment between an observed distribution of a third feature in the plurality of data points, and a reference distribution of the third feature in the semantic data type; calculating a total score for the semantic data type from the first, second, and third scores; determining an initial ranking of the total score in comparison with another total score reflecting the first, second, and third features in another semantic data type; identifying a fourth feature differentiating between the semantic data type and the other semantic data type; assigning a final ranking to the total score and the other total score by, determining alignment between an observed distribution of the fourth feature in the plurality of data points, and reference distributions of the fourth feature in the semantic data type and in the other semantic data type; assigning the semantic data type to the plurality of data points based upon the final ranking; and storing the plurality of data points with metadata indicating the semantic data type. 11. A non-transitory computer readable storage medium as in claim 10 wherein the semantic data type comprises an integer, a date, a month, a day, an identifier, an IP address, a currency transaction, or a currency balance. 12. A non-transitory computer readable storage medium as in claim 10 wherein the second feature comprises a data point length, a data point first digit, other than a first digit of a data point, a dispersion, a number of digits after a decimal point. 13. A non-transitory computer readable storage medium as in claim 10 wherein the method further comprises: deriving the reference distribution of the second feature from training data; receiving feedback regarding accuracy of the assignment of semantic data type; and updating the training data to reflect the feedback. 14. A non-transitory computer readable storage medium as in claim 10 wherein the method further comprises: receiving feedback regarding accuracy of the assignment of semantic data type; calculating the total score by assigning respective weight coefficients to the first, second, and third scores; and updating the respective weight coefficients based upon the feedback. 15. A non-transitory computer readable storage medium as in claim 10 wherein converting the plurality of data points to the semantic data type employs a pattern matching mechanism comprising regular expressions specifying class-specific search patterns. 16. A computer system comprising: one or more processors; a software program, executable on said computer system, the software program configured to cause an in-memory database engine to: receive a plurality of data points lacking associated metadata; determine a first score of a first feature comprising a success rate converting the plurality of data points to a semantic data type; determine a second score from alignment between an observed distribution of a second feature in the plurality of data points, and a reference distribution of the second feature in the semantic data type; determine a third score from alignment between an observed distribution of a third feature in the plurality of data points, and a reference distribution of the third feature in the semantic data type; calculate a total score for the semantic data type from the first, second, and third scores; determine an initial ranking of the total score in comparison with another total score reflecting the first, second, and third features in another semantic data type; identify a fourth feature differentiating between the semantic data type and the other semantic data type; assign a final ranking to the total score and the other total score by, determine alignment between an observed distribution of the fourth feature in the plurality of data points, and reference distributions of the fourth feature in the semantic data type and in the other semantic data type; assign the semantic data type to the plurality of data points based upon the final ranking; and store the plurality of data points in a column of a table of an in-memory database with metadata indicating the semantic data type. 17. A computer system as in claim 16 wherein the software is further configured to cause the in-memory database engine to: calculate the alignment between the observed distribution of the second feature and the reference distribution of the second feature as a Kolmogorov-Smirnov distance. 18. A computer system as in claim 16 wherein the software is further configured to cause the in-memory database engine to: receive feedback regarding accuracy of the assignment of semantic data type; calculate the total score by assigning respective weight coefficients to the first, second, and third scores; and update the respective weight coefficients based upon the feedback. 19. A computer system as in claim 16 wherein the software is further configured to cause the in-memory database engine to: derive the reference distribution of the second feature from training data stored in the in-memory database; receive feedback regarding accuracy of the assignment of semantic data type; and update the training data to reflect the feedback. 20. A computer system as in claim 16 wherein the software is further configured to cause the in-memory database engine to convert the plurality of data points to the semantic data type by pattern matching comprising regular expressions specifying class-specific search patterns.