KT NI VO ORACLE - Bai 3: Cu hinh client side kt ni

KT NI VO ORACLE - Bai 3: Cu hinh Client side kt ni

Tc gi: www.oravn.com

Ni dung bai nay se tom lc mt s khai nim cn bit khi tao kt ni vi Oracle database va hng dn cac ban tng bc cu hinh kt ni theo hai phng thc Host naming va Local naming.

1. Mt s khai nim cn bit:

a) Database Service: i vi client thi database la mt dich vu (service), no thc thi cng vic thay cho client. y dich vu ma database cung cp cho client chinh la lu tr d liu va goi lai d liu khi cn. Khi kt ni client nhn bit database qua tn dich vu (service name) mc inh la bng vi global database name (cac ban xem lai phn tao listener bai 2).

b) Naming Methods: khi yu cu kt ni vi Oracle database user phai cung cp mt chui kt ni (connect string) gm username, password va tn kt ni (connect identifier). Connect identifier co th la mt chui m ta chi tit thng tin kt ni vi database (goi la connect descriptor) hoc database service name hay mt cai tn thay th connect descriptor.

Naming method la phng phap ma Oracle Net client s dung chuyn mt connect identifier thanh connect descriptor khi thc hin kt ni vi database. Cung luc, client co th chon s dung nhiu naming method khac nhau.

*** Oracle Net cung cp cac naming methods sau:

- Local Naming: xat inh ia chi mang bng cach s dung thng tin cu hinh (service names va cac connect descriptors) lu trong mt file tai mi client tn la tnsnames.ora

- Directory Naming: lu tr cac connect identifier tm trung trong mt LDAP-compliant directory server dung truy cp n database service

- Oracle Names: s dung chinh database Oracle lu tn va ia chi cua cac database. Client mun kt ni vi database phai kt ni n Oracle Names server, sau o tuy theo tn ma client cung cp, Oracle Names server se tra lai thng tin ia chi mang cua database server cho client.

- Host Naming: cho phep client s dung bi danh (host name alias) kt ni vi Oracle database server. Tn may (host name) anh xa n service_names cua database server trong Domain Name System (DNS), Network Information Service (NIS), hoc trong file hosts th muc /etc i vi h iu hanh Linux, Unix hay %winsys%/drivers/etc vi Windows.

- External Naming: s dung dich vu tn min cua hang th ba (third-party naming service)

c) Connect string:

username/password@connect_identifier connect_identifier y thng la mt tn thay th theo cac naming method noi trn.

d) Chi ra cac naming method: click chon Net Configuration Assistant

Khi kt thuc thng tin c lu trong file oracle_home/network/admin/sqlnet.ora. y la text file co th d dang chinh sa bng tay sau o. Hinh bn la ni dung cua mt file sqlnet.ora cho thy co hai naming method c chon la local naming va host naming.

2. Cu hinh HOSTNAME

Yu cu cu hinh kt ni theo phng thc host naming rt n gian. Trc tin cac ban chon naming method nay, tc tao file sqlnet.ora vi ni dung NAMES.DIRECTORY_PATH=(HOSTNAME). Tip theo, cac ban thm cac thng tin sau vao file host: IP, hostname, service_names (gia tri cua thng s global_dbname trong cu hinh listener). Mi gia tri cach nhau khoang trng hoc tab. Tom lai theo phng thc nay phia client se cu hinh trong hai file la sqlnet.ora va host.

Vi du: cac ban thm vao file host nhng thng tin sau:

Cac ban co th co hai connect string la username/password@ORA.ORAVN.COM hoc username/password@EDUDB kt ni n database service trn may khoatn

*** iu kin bt buc i vi host naming:

- client phai cai phn mm Oracle Net Services Client

- client va server kt ni qua giao thc TCP/IP

3. Cu hinh TNSNAME

Hay con goi la local name. Phng thc nay oi hoi service name c lu trong file tnsnames.ora tai client. Nh vy, client se cu hinh file sqlnet.ora chon s dung phng thc local naming va tao file tnsnames.ora. Cac ban co th s dung cng cu Oracle Net Configuration Assistant theo cac bc sau:

service name phai bng vi cac gia tri khai bao trong thng s global_dbname cua listener.

gia tri cua thng s host name co th la ia chi IP hoc hostname. Tng t, port cung phai bng vi port khai bao listener.

tn bt ky ma cac ban mun t, thng la trung vi service name

khi kt thuc no se tao mi file tnsnames.ora lu lai cac thng s khai bao hoc se lu ni thm vao mt file co sn. Vi du bn di la ni dung file tnsnames.ora vi hai net service name c khai bao la EDUDB va ORAINS

kt ni n database service ORA.ORAVN.COM cac ban se khai bao connect string la username/password@ORAINS hoc username/password@EDUDB kt ni vi service EDUDB.