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Mapping dari ERD ke Tabel Pertemuan Keempat. Algoritma 1  Untuk setiap entitas kuat EK, buat tabel baru EK yang memasukkan semua attribut sederhana (simple.

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Presentasi berjudul: "Mapping dari ERD ke Tabel Pertemuan Keempat. Algoritma 1  Untuk setiap entitas kuat EK, buat tabel baru EK yang memasukkan semua attribut sederhana (simple."— Transcript presentasi:

1 Mapping dari ERD ke Tabel Pertemuan Keempat

2 Algoritma 1  Untuk setiap entitas kuat EK, buat tabel baru EK yang memasukkan semua attribut sederhana (simple attribut)  Untuk atribut komposit, hanya atribut sederhananya yang disertakan  Pilih salah satu key attribute dari EK sebagai primary key. Jika key yang terpilih merupakan atribut komposit, seluruh atribut sederhananya merupakan primary key

3 Algoritma 1 Langkah 1 Tabel PEGAWAI NoKTP NmDepan Inisial NmBlk JenisKel Alamat Gaji Atribut komposit nama tidak menjadi field/kolom pada tabel PEGAWAI, tetapi yg dimasukkan adalah bagian simple attributnya.

4 Algoritma 2  Untuk setiap entitas lemah EL yang dimiliki oleh entitas kuat EK, buat tabel baru EL yang memasukkan semua atribut sederhana EL  Tambahkan pada EL foreign key yang diambil dari primary key EK  Primary key yang dibentuk merupakan gabungan primary key EK dan partial key dari EL (jika ada)

5 Algoritma 2 Langkah 2 Tabel TANGGUNGAN Peg_NoKTP Nama JenisKel TglLahir Hubungan

6 Algoritma 3 Untuk setiap relasi 1:1 antara entitas EK1 dan EK2:  Jika sama-sama merupakan partisipasi total, pilih salah satu. Tambahkan semua semua simple attribut dari entitas yang lain  Jika sama-sama merupakan partisipasi parsial, pilih salah satu. Tambahkan foreign key dari primary key entitas yang lain  Jika salah satu merupakan partisipasi total, pilih yang berpartisipasi total. Tambahkan foreign key dari primary key entitas yang lain Kemudian tambahkan semua simple atribut dari relasi tersebut

7 Algoritma 3 Langkah 1-3 Tabel DEPARTEMEN … … Peg_NoKTPKepala Kolom-kolom yang telah dibentuk pada langkah-langkah sebelumnya

8 Algoritma 4  Untuk setiap relasi 1:N antara entitas EK1 dan EK2, pilih entitas yang memiliki derajat maksimum relasi=1  Tambahkan sebuah foreign key dari primary key entitas lain yang memiliki derajat maksimum relasi = N  Tambahkan pula seluruh atribut dari relasi tersebut

9 Algoritma 4 Langkah 4 Tabel PEGAWAI … … Dep_NomorBekerja Dep_NamaBekerja Kolom-kolom yang telah dibentuk pada langkah-langkah sebelumnya

10 Algoritma 5  Untuk setiap relasi M:N antara entitas EK1 dan EK2, buat tabel baru MN  Tambahkan seluruh simple attribut dari relasi tersebut  Tambahkan pula foreign key yang diambil dari primary key masing-masing entitas yang direlasikan  Primary key merupakan gabungan dari seluruh foreign key tersebut

11 Algoritma 5 Langkah 5 Tabel BEKERJAPADA Peg_NoKTP Pro_Nomor Pro_Nama LamaJam

12 Algoritma 6  Untuk setiap multivalued attribute, buat tabel baru MV  Tambahkan seluruh simple attributnya  Tambahkan pula sebagai foreign key, primary key dari entitas yang memiliki  Primary key merupakan gabungan dari dari seluruh fieldnya

13 Algortima 6 Langkah 6 Tabel DEP_LOKASI Dep_Nomor Dep_Nama Lokasi

14 ERD Perusahaan

15 Contoh Berdasarkan ERD NoKTPNmDepanInisialNmBlkJenisKelAlamatGaji Step 1: Langkah pertama mendefinisikan entitas kuat Tabel Pegawai Entitas pegawai memiliki atribut NoKTP,JenisKel,Alamat,Gaji dan atribut composit Nama (NmDepan,Inisial,NmBlk). Sehingga skema tabel pegawai sbb: Tabel Departemen Entitas departemen memiliki atribut Nomor,Nama, JmlPegawai dan atribut multi valued lokasi yang bisa menjadi tabel lain yang mengacu ke tabel departemen. Skemanya adalah sbb: NomorNamaJmlPegawai

16 Contoh NomorNamaLokasi Tabel proyek Entitas proyek terdiri dari atribut Nomor, Nama,Lokasi. Skema dari tabel proyek adalah Step 2: Langkah kedua adalah mendefinisikan entitas lemah Tabel Tanggungan Entitas tanggungan bergantung pada entitas pegawai. Atibutnya adalah Nama,JenisKel,TglLahir,Hubungan. Primary key dari entitas pegawai masuk ke entitas tanggungan NoKTPNamaJenisKelTglLahirHubungan

17 Contoh NomorNamaJmlPegawaiNoKTPTglMulai Step 3: Tabel Departemen Pada relasi mengepalai, suatu departemen dikepalai oleh 1 pegawai sehingga primary key entitas pegawai masuk ke entitas departemen, ditambahkan dengan atribut tglMulai Step 4: Tabel Pegawai Pada relasi memimpin dan bekerja, primary key dari departemen masuk ke entitas pegawai dan setiap pegawai memiliki pimpinan NoKTPNmDepanInisialNmBlkJenisKelAlamatGaji …NoKTP_Pimpinandep_nomorDep_nama

18 Contoh Tabel Proyek Berdasarkan relasi mengatur, maka primary key dari entitas departemen masuk ke entitas proyek NomorNamaLokasidep_nomor dep_nama dep_nama Step 5: Tabel BekerjaPada Pada relasi bekerja pada memiliki relasi many to many sehingga akan muncul tabel baru yang primary keynya berasal dari entitas pegawai dan proyek noKTP proyek_nomor proyek_namalamaJam

19 Contoh Step 6: Tabel Departemen_Lokasi Dari atribut muti valued lokasi akan dibuat tabel baru yang skemanya sebagai berikut dep_nomor dep_nama Lokasi Lokasi

20 ER-to-Relational Mapping  ER-to-Relational Mapping Algorithm  Step 1: Mapping of Regular Entity Types  Step 2: Mapping of Weak Entity Types  Step 3: Mapping of Binary 1:1 Relation Types  Step 4: Mapping of Binary 1:N Relationship Types.  Step 5: Mapping of Binary M:N Relationship Types.  Step 6: Mapping of Multivalued attributes.  Step 7: Mapping of N-ary Relationship Types.

21 ER-to-Relational Mapping Step 1: Mapping of Regular Entity Types. Step 1: Mapping of Regular Entity Types.  For each regular (strong) entity type E in the ER schema, create a relation R that includes all the simple attributes of E.  Choose one of the key attributes of E as the primary key for R.  If the chosen key of E is composite, the set of simple attributes that form it will together form the primary key of R. Example: We create the relations EMPLOYEE, DEPARTMENT, and PROJECT in the relational schema corresponding to the regular entities in the ER diagram. Example: We create the relations EMPLOYEE, DEPARTMENT, and PROJECT in the relational schema corresponding to the regular entities in the ER diagram. SSN, DNUMBER, and PNUMBER are the primary keys for the relations EMPLOYEE, DEPARTMENT, and PROJECT as shown. SSN, DNUMBER, and PNUMBER are the primary keys for the relations EMPLOYEE, DEPARTMENT, and PROJECT as shown.

22 FIGURE 7.1 The ER conceptual schema diagram for the COMPANY database.

23 FIGURE 7.2 Result of mapping the COMPANY ER schema into a relational schema.

24 ER-to-Relational Mapping (contd.) Step 2: Mapping of Weak Entity Types Step 2: Mapping of Weak Entity Types a. For each weak entity type W in the ER schema with owner entity type E, create a relation R & include all simple attributes (or simple components of composite attributes) of W as attributes of R. b. Also, include as foreign key attributes of R the primary key attribute(s) of the relation(s) that correspond to the owner entity type(s). c. The primary key of R is the combination of the primary key(s) of the owner(s) and the partial key of the weak entity type W, if any. Example: Create the relation DEPENDENT in this step to correspond to the weak entity type DEPENDENT. Example: Create the relation DEPENDENT in this step to correspond to the weak entity type DEPENDENT. Include the primary key SSN of the EMPLOYEE relation as a foreign key attribute of DEPENDENT (renamed to ESSN). Include the primary key SSN of the EMPLOYEE relation as a foreign key attribute of DEPENDENT (renamed to ESSN). The primary key of the DEPENDENT relation is the combination {ESSN, DEPENDENT_NAME} because DEPENDENT_NAME is the partial key of DEPENDENT. The primary key of the DEPENDENT relation is the combination {ESSN, DEPENDENT_NAME} because DEPENDENT_NAME is the partial key of DEPENDENT.

25 ER-to-Relational Mapping (contd.)  Step 3: Mapping of Binary 1:1 Relation Types For each binary 1:1 relationship type R in the ER schema, identify the relations S and T that correspond to the entity types participating in R. For each binary 1:1 relationship type R in the ER schema, identify the relations S and T that correspond to the entity types participating in R. Choose one of the relations-say S-and include a foreign key in S the primary key of T. It is better to choose an entity type with total participation in R in the role of S. Choose one of the relations-say S-and include a foreign key in S the primary key of T. It is better to choose an entity type with total participation in R in the role of S.  Example: 1:1 relation MANAGES is mapped by choosing the participating entity type DEPARTMENT to serve in the role of S, because its participation in the MANAGES relationship type is total.

26 ER-to-Relational Mapping (contd.) Step 4: Mapping of Binary 1:N Relationship Types. Step 4: Mapping of Binary 1:N Relationship Types. For each regular binary 1:N relationship type R, identify the relation S that represent the participating entity type at the N-side of the relationship type. For each regular binary 1:N relationship type R, identify the relation S that represent the participating entity type at the N-side of the relationship type. Include as foreign key in S the primary key of the relation T that represents the other entity type participating in R. Include as foreign key in S the primary key of the relation T that represents the other entity type participating in R. Include any simple attributes of the 1:N relation type as attributes of S. Include any simple attributes of the 1:N relation type as attributes of S. Example: 1:N relationship types WORKS_FOR, CONTROLS, and SUPERVISION in the figure. Example: 1:N relationship types WORKS_FOR, CONTROLS, and SUPERVISION in the figure. For WORKS_FOR we include the primary key DNUMBER of the DEPARTMENT relation as foreign key in the EMPLOYEE relation and call it DNO. For WORKS_FOR we include the primary key DNUMBER of the DEPARTMENT relation as foreign key in the EMPLOYEE relation and call it DNO.

27 ER-to-Relational Mapping (contd.)  Step 5: Mapping of Binary M:N Relationship Types. For each regular binary M:N relationship type R, create a new relation S to represent R. For each regular binary M:N relationship type R, create a new relation S to represent R. Include as foreign key attributes in S the primary keys of the relations that represent the participating entity types; their combination will form the primary key of S. Include as foreign key attributes in S the primary keys of the relations that represent the participating entity types; their combination will form the primary key of S. Also include any simple attributes of the M:N relationship type (or simple components of composite attributes) as attributes of S. Also include any simple attributes of the M:N relationship type (or simple components of composite attributes) as attributes of S.  Example: The M:N relationship type WORKS_ON from the ER diagram is mapped by creating a relation WORKS_ON in the relational database schema. The primary keys of the PROJECT and EMPLOYEE relations are included as foreign keys in WORKS_ON and renamed PNO and ESSN, respectively. The primary keys of the PROJECT and EMPLOYEE relations are included as foreign keys in WORKS_ON and renamed PNO and ESSN, respectively. Attribute HOURS in WORKS_ON represents the HOURS attribute of the relation type. The primary key of the WORKS_ON relation is the combination of the foreign key attributes {ESSN, PNO}. Attribute HOURS in WORKS_ON represents the HOURS attribute of the relation type. The primary key of the WORKS_ON relation is the combination of the foreign key attributes {ESSN, PNO}.

28 ER-to-Relational Mapping (contd.)  Step 6: Mapping of Multivalued attributes. For each multivalued attribute A, create a new relation R. For each multivalued attribute A, create a new relation R. This relation R will include an attribute corresponding to A, plus the primary key attribute K-as a foreign key in R-of the relation that represents the entity type of relationship type that has A as an attribute. This relation R will include an attribute corresponding to A, plus the primary key attribute K-as a foreign key in R-of the relation that represents the entity type of relationship type that has A as an attribute. The primary key of R is the combination of A and K. If the multivalued attribute is composite, we include its simple components. The primary key of R is the combination of A and K. If the multivalued attribute is composite, we include its simple components.  Example: The relation DEPT_LOCATIONS is created. The attribute DLOCATION represents the multivalued attribute LOCATIONS of DEPARTMENT, while DNUMBER-as foreign key- represents the primary key of the DEPARTMENT relation. The attribute DLOCATION represents the multivalued attribute LOCATIONS of DEPARTMENT, while DNUMBER-as foreign key- represents the primary key of the DEPARTMENT relation. The primary key of R is the combination of {DNUMBER, DLOCATION}. The primary key of R is the combination of {DNUMBER, DLOCATION}.

29 ER-to-Relational Mapping (contd.)  Step 7: Mapping of N-ary Relationship Types. For each n-ary relationship type R, where n>2, create a new relationship S to represent R. For each n-ary relationship type R, where n>2, create a new relationship S to represent R. Include as foreign key attributes in S the primary keys of the relations that represent the participating entity types. Include as foreign key attributes in S the primary keys of the relations that represent the participating entity types. Also include any simple attributes of the n-ary relationship type (or simple components of composite attributes) as attributes of S. Also include any simple attributes of the n-ary relationship type (or simple components of composite attributes) as attributes of S.  Example: The relationship type SUPPY in the ER on the next slide. This can be mapped to the relation SUPPLY shown in the relational schema, whose primary key is the combination of the three foreign keys {SNAME, PARTNO, PROJNAME} This can be mapped to the relation SUPPLY shown in the relational schema, whose primary key is the combination of the three foreign keys {SNAME, PARTNO, PROJNAME}


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