Class IndexMetaData

  • All Implemented Interfaces:
    java.io.Serializable

    public class IndexMetaData
    extends ConstraintMetaData
    For schema generation, it might be useful to specify that a column or columns be indexed, and to provide the name of the index. For this purpose, an index element can be contained within a field, element, key, value, or join element, and this indicates that the column(s) associated with the referenced element should be indexed. Indexes can also be specified at the class level, by including index elements containing column elements. In this case, the column elements are mapped elsewhere, and the column elements contain only the column name.
    See Also:
    Serialized Form
    • Field Detail

      • unique

        boolean unique
        You can use UNIQUE constraints to ensure that no duplicate values are entered in specific columns that do not participate in a primary key. Although both a UNIQUE constraint and a PRIMARY KEY constraint enforce uniqueness, use a UNIQUE constraint instead of a PRIMARY KEY constraint when you want to enforce the uniqueness of:
        • A column, or combination of columns, that is not the primary key. Multiple UNIQUE constraints can be defined on a table, whereas only one PRIMARY KEY constraint can be defined on a table.
        • A column that allows null values. UNIQUE constraints can be defined on columns that allow null values, whereas PRIMARY KEY constraints can be defined only on columns that do not allow null values.
        A UNIQUE constraint can also be referenced by a FOREIGN KEY constraint.
    • Constructor Detail

      • IndexMetaData

        public IndexMetaData()
      • IndexMetaData

        public IndexMetaData​(IndexMetaData imd)
        Copy constructor.
        Parameters:
        imd - The metadata to copy
    • Method Detail

      • isUnique

        public final boolean isUnique()