• Mapping EER to Codaysl or relational database schema
• Mapping of an OOP to relational database schema
• Mapping of OOP to OOP database schem

1. Create record for every entity type
2. Create a seperate secord type for a weak entity type
3. Create a set type for every binary 1:n relationship type
4. Create a set type for every binary 1:1 relationship type
5. Create extra dummy record for every binary n:m relationship
6. Create extra dummy record for every recursive relationship type
7. Create extra dummy record type for a ternary relationship type
8. Create record type for super class that becomes owner in set types with subclasses as members: cannot guarantee that each set contains 1 member and cannot indicate specialtisation

EER to Relational

Step 1

1. For each entity type create a relation that includes all the simple attributes
2. Include only simple component attributes of composite attribute
3. Choose one of the key attributes as primary key 
4. if chosen key is compiste the set of simple attributes that form it will make the primary key

EER to Relation

Step 2

1. For weak entity types W with owner entity type E, create relation R that includes all the simple attributes of W.
2. Include as foreign key attributes of R the primary key attributes of the relation
3. The primary key of R is the combination of the primary key of the owner and the partial key of the weak entity type W

EER to Relation 

Step 3

1. For each binary 1:1 relationship type R indentify the relations S and T that correspond to the entity types participating in R
2. Choose one of the relations S, and include as foreign key in S the primary key of T
3. Better to chose an entity type with total participation in R in the role of S
4. Include all the simple attrbutes of the 1:1 relationship type R as attribute of S

EER to Relational 

Step 4

1. For each binary 1:N relationship type R identify the relation S that repersents the participation entity type at the N-side of the relationship type
2. Includ as foreign key in S the primary key of the relation T that repersents the other enttity type praticipating in R.
3. Include all the simple attributes of the 1:N relationship type as attributes of S.

EER to Relational

Step 5

1. For each binary M:N relationship type R create a new relation S to repersent R
2. Include as foreign key attrivutes in S the primary keys of the relations that repersent the participating entity types;
3. Include all the simple attributes of the M:N relationship type as attributes of S

ERR to Relation

Step 6

1. For each multivalued attribute A create a new relation R
2. R will include attribute of A plus the primary key attribute k as the foreign key in R
3. primary key of R is the combination of A and K
4. if multivalued is composite include simple components

EER to Relational

Step 7

1. For each n-ary relationship R where n>2 create new relation S to repersent R
2. Include as foreign key attributes in S the primary keys of the relations that represent the participating entity types
3. include any simple attributes of relationship type as attribute of S
4. primary key of S is usually a combination of all the foreign keys that reference the relations repersenting the participation entity types 
5. if cardinatlity constraints on any of the enitty types R participating in R is 1 then primary key of S should not include the foreign key attrbute that references relation E' corresponding to E

1. Cannot guarentee that a manager of a department also works in the department
2. cannot guarentee that employees should work on projects assigned to their departments
3. cannot guarantee that a department has at minimum on employee
4. the same employee can manage multiple department