#Oracle schema copy space usage update#

NOTE! I highly recommend you don't do this in production. Run them all and you've got yourself a copy. Keep moving through the wizard and it should export multiple scripts to run. Then select the objects and click the right arrow, or click the double right arrow to select all objects. In the 'Specify objects' area, Click 'More' and choose the source schema. Then, select which objects you want to copy.

I f using SQL Developer: Tools -> Database exportĬhoose the source Database and Ensure 'Export DDL' is checked (if you want to copy the objects as well). If any of the objects use functions/procedures from other schemas, you'll need to ensure that either the correct permissions are set up, or you run this as DBA/SYS. Then log in as the SC2 schema user (or as DBA/SYS) and deploy the SC2 schema objects using the 'deploy all' script that comes with the export. You can choose to copy an entire schema (SC1, in your case) and then ensure that it has However, an INSTEAD OF trigger does not change the read-only or updatable property of the view itself.If using Toad: Database -> Export -> Generate Schema Script Thus database systems can implement data modifications based on read-only views. This technique allows the definition of other logic for execution in place of an insert, update, or delete operation on the views. Some systems support the definition of INSTEAD OF triggers on views.

#Oracle schema copy space usage update#

A view update is done by key preservation. Read-only views do not support such operations because the DBMS cannot map the changes to the underlying base tables. INSERT, UPDATE, and DELETE operations can be performed on updatable views. If the database system can determine the reverse mapping from the view schema to the schema of the underlying base tables, then the view is updatable. And at some point if the server is at 100 CPU and 100 memory usage. Nevertheless, some DBMS (such as Oracle Database) do not abide by this SQL standard restriction.ĭatabase practitioners can define views as read-only or updatable. johnpau2013 wrote:If we have Oracle database with multiple schemas. However, sorted data can be obtained from a view, in the same way as any other table - as part of a query statement on that view. Therefore, an ORDER BY clause in the view definition is meaningless the SQL standard ( SQL:2003) does not allow an ORDER BY clause in the subquery of a CREATE VIEW command, just as it is refused in a CREATE TABLE statement. Since sets are not ordered - by definition - neither are the rows of a view. A view is a relational table, and the relational model defines a table as a set of rows. Just as rows in a base table lack any defined ordering, rows available through a view do not appear with any default sorting. Views can make it easier to create lossless join decomposition. Without the use of views, the normalization of databases above second normal form would become much more difficult. In another parallel with functions, database users can manipulate nested views, thus one view can aggregate data from other views. Just as a function (in programming) can provide abstraction, so can a database view. Depending on the SQL engine used, views can provide extra security.

Views take very little space to store the database contains only the definition of a view, not a copy of all the data that it presents.For example, a view could appear as Sales2000 or Sales2001, transparently partitioning the actual underlying table. Views can hide the complexity of data.Views can act as aggregated tables, where the database engine aggregates data ( sum, average, etc.) and presents the calculated results as part of the data.Views can join and simplify multiple tables into a single virtual table.Consequently, a view can limit the degree of exposure of the underlying tables to the outer world: a given user may have permission to query the view, while denied access to the rest of the base table. Views can represent a subset of the data contained in a table.Views can provide advantages over tables: In some NoSQL databases, views are the only way to query data. Changes applied to the data in a relevant underlying table are reflected in the data shown in subsequent invocations of the view.

Unlike ordinary base tables in a relational database, a view does not form part of the physical schema: as a result set, it is a virtual table computed or collated dynamically from data in the database when access to that view is requested. This pre-established query command is kept in the database dictionary. In a database, a view is the result set of a stored query on the data, which the database users can query just as they would in a persistent database collection object.

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