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Oracle Database (SQL (There are four types of syntactical variants (DCL -…
Oracle Database
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Database Architecture
Memory Structures
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System Global Area (SGA) - Partitioned collection of memory allocated to substructures removing contention with storage resources. Memory needs to be sized for this area.
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Log Buffer - Staging area for redo log. The redo log is a transaction log of all of the changes made.
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Processes
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DBWn - Writes memory buffers to disk. When changes are committed this process handles the writes. There can be more than one of these processes emphasised by the n.
LGWR - Periodically flushes the Redo Log Buffer in memory and writes them to the Redo Log File on disk.
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Relational Database
A database is a organised collection of data treated as a single unit. A relational database is a specific type of database stores data in tables.
A relational database has more than one table and the tables are linked using key fields. This is advantageous because mistakes will be less likely to happen. In the event of a mistake, correcting it will correct the mistake database-wide. Additionally, duplication is avoided keeping the size down.
DBMS
A DBMS is certain software used to store, protect and access data. By store we mean storing the data in files. By protect we mean using ACL's or encryption. By access, you need a way of accessing the data which is where the SQL language comes in.
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