In data warehousing, it is common to combine the conceptual data model and the logical data model to a single step. The steps for logical data model are indicated below: Identify all entities. Identify primary keys for all entities. Find the relationships between different entities. Find all attributes for each entity. Resolve all entity relationships that is many-to-many relationships. Normalization if required. The environment provides the infrastructure to carry out the specified process. It consists of: A which is built from a conceptual multidimensional refined conceptual schema, schema enriched with design guidelines. The and the source schema DW schema. Schema which are used to represent correspondences between the mappings, conceptual schema and the source schema. A set of which apply the to the source schema design rules, schema transformations in order to build the DW schema. A set of pre-defined that new relations from existing schema transformations ones, applying DW design techniques. A which keeps the transformations that where applied, providing transformation the mappings between source and DW schemas. Logical Design compared with Physical Design The process of logical design involves arranging data into a series of logical relationships called entities and attributes. An represents a chunk of information. In relational databases, an entity often maps to a table. An is a component of an entity that helps define the uniqueness of the entity. In relational databases, an attribute maps to a column.
In data warehousing, it is common to combine the conceptual data model and the logical data model to a single step. The steps for logical data model are indicated below: Identify all entities. Identify primary keys for all entities. Find the relationships between different entities. Find all attributes for each entity. Resolve all entity relationships that is many-to-many relationships. Normalization if required. The environment provides the infrastructure to carry out the specified process. It consists of: A refined conceptual schema, which is built from a conceptual multidimensional schema enriched with design guidelines. The source schema and the DW schema. Schema mappings, which are used to represent correspondences between the conceptual schema and the source schema. A set of design rules, which apply the schema transformations to the source schema in order to build the DW schema. A set of pre-defined schema transformations that new relations from existing ones, applying DW design techniques. A transformation which keeps the transformations that where applied, providing the mappings between source and DW schemas. Logical Design compared with Physical Design The process of logical design involves arranging data into a series of logical relationships called entities and attributes. An represents a chunk of information. In relational databases, an entity often maps to a table. An is a component of an entity that helps define the uniqueness of the entity. In relational databases, an attribute maps to a column.
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