Step 3 Translate logical data model for target DBMS Step 3.1 Design base relations Step 3.2 Design representation of derived data Step 3.3 Design general constraints Step 4 Design file organizations and indexes Step 4.1 Analyze transactions Step 4.2 Choose file organizations Step 4.3 Choose indexes Step 4.4 Estimate disk space requirements Step 5 Design user views Step 6 Design security mechanisms Step 7 Consider the introduction of controlled redundancy Step 8 Monitor and tune the operational system This methodology can be used to design relatively simple to highly complex database sys- tems. Just as the database design stage of the database systems development lifecycle (see Section 9.6) has three phases, namely conceptual, logical, and physical design, so too has the methodology. Step 1 creates a conceptual database design, Step 2 creates a logical database design, and Steps 3 to 8 creates a physical database design. Depending on the complexity of the database system being built, some of the steps may be omitted. For example, Step 2.6 of the methodology is not required for database systems with a single user view or database systems with multiple user views being managed using the central- ization approach (see Section 9.5). For this reason, we only refer to the creation of a single conceptual data model in Step 1 or single logical data model in Step 2. However, if the database designer is using the view integration approach (see Section 9.5) to manage user views for a database system then Steps 1 and 2 may be repeated as necessary to create the required number of models, which are then merged in Step 2.6. In Chapter 9, we introduced the term ‘local conceptual data model’ or ‘local logical data model’ to refer to the modeling of one or more, but not all, user views of a database sys- tem and the term ‘global logical data model’ to refer to the modeling of all user views of a database system. However, the methodology is presented using the more general terms ‘conceptual data model’ and ‘logical data model’ with the exception of the optional Step 2.6, which necessitates the use of the terms locallogical data model and globallogical data model as it is this step that describes the tasks necessary to merge separate local logical data models to produce a global logical data model. An important aspect of any design methodology is to ensure that the models produced are repeatedly validated so that they continue to be an accurate representation of the part of the enterprise being modeled. In this methodology the data models are validated in various ways such as by using normalization (Step 2.2), by ensuring the critical trans- actions are supported (Steps 1.8 and 2.3) and by involving the users as much as possible (Steps 1.9 and 2.5).