السلام عليكم

ما مفهوم الMetadata

ويا ريت توضيح اهميتها

ونريد شرح هذا المثال ايضا بتقصيل معنى كلمات الكومند

expdp directory=dpump_dir dumpfile=metadata.dmp content=metadata_only

expdp directory=dpump_dir dumpfile=metadata.dmp content=metadata_only schemas=ACCMAIN, HRMAIN

Hello Waziry,

Metadata is a data about data.it is the description of any thing in the life.

we can say that the METADATA REPOSITORY is a database for data about your original data.
it is useful to provide us a consistent and reliable way to access our data. This METADATA REPOSITORY can be saved in physical location on your hard or may be a virtual database.

METADATA may include information and data about how to access specific table data in shortest way (the best performance way) or more detail about this table.

A metadata repository is a database of data about data (metadata). The purpose of the metadata repository is to provide a consistent and reliable means of access to data. The repository itself may be stored in a physical location or may be a virtual database, in which metadata is drawn from separate sources. Metadata may include information about how to access specific data, or more detail about it, among a myriad of possibilities.

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expdp system/sys directory=dpump_dir dumpfile=metadata.dmp content=metadata_only

the meaning of this command is:

expdp: is the command utility

system/sys: is the username/password for the privileged user that can make the export process

directory=dpump_dir: is the defined OS directory that the export file will be located as your needs (must have CREATE DIRECTORY privilege) and created by (Create Directory dbump_dir as 'C:\export\' )

dumpfile=metadata.dmp: is the descriptive name of exported file that you choose by yourself

content=metadata_only: is determine the data we need to export and it can be ALL(default) , METADATA_ONLY (the objects without data), DATA_ONLY

THANKS,