dawidwys commented on a change in pull request #10213: [FLINK-12846][table-common] Carry primary key information in TableSchema URL: https://github.com/apache/flink/pull/10213#discussion_r346828666
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/api/TableSchema.java ########## @@ -22,32 +22,57 @@ import org.apache.flink.api.common.typeinfo.TypeInformation; import org.apache.flink.api.common.typeutils.CompositeType; import org.apache.flink.table.types.DataType; -import org.apache.flink.table.types.FieldsDataType; -import org.apache.flink.table.types.logical.LogicalType; import org.apache.flink.table.types.utils.TypeConversions; import org.apache.flink.types.Row; import org.apache.flink.util.Preconditions; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; -import java.util.HashMap; import java.util.List; -import java.util.Map; import java.util.Objects; import java.util.Optional; import java.util.stream.Collectors; import java.util.stream.IntStream; +import static java.util.Collections.emptyList; import static org.apache.flink.table.api.DataTypes.FIELD; import static org.apache.flink.table.api.DataTypes.Field; import static org.apache.flink.table.api.DataTypes.ROW; -import static org.apache.flink.table.types.logical.LogicalTypeRoot.TIMESTAMP_WITHOUT_TIME_ZONE; import static org.apache.flink.table.types.utils.TypeConversions.fromDataTypeToLegacyInfo; import static org.apache.flink.table.types.utils.TypeConversions.fromLegacyInfoToDataType; +import static org.apache.flink.table.utils.TableSchemaValidation.validateNameTypeNumberEqual; +import static org.apache.flink.table.utils.TableSchemaValidation.validateSchema; /** - * A table schema that represents a table's structure with field names and data types. + * A table schema that represents a table's structure with field names, data types and + * constraint information (e.g. primary key, unique key). + * + * <p>Concepts about primary key and unique key:</p> + * <ul> + * <li> + * Primary key and unique key can consist of single or multiple columns (fields). + * </li> + * <li> + * A primary key or unique key on source will be simply trusted, we won't validate the + * constraint. The primary key and unique key information will then be used for query + * optimization. If a bounded or unbounded table source defines any primary key or + * unique key, it must contain a unique value for each row of data. You cannot have + * two records having the same value of that field(s). Otherwise, the result of query + * might be wrong. + * </li> + * <li> + * A primary key or unique key on sink is a weak constraint. Currently, we won't validate Review comment: I don't necessarily understand the first sentence. What do you mean by weak constraint? Is it weak because we do not support that yet? ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
