External Table Loads → An external table load creates an external table for data that is contained in a datafile. The load … advantages of using external table loads over conventional path and direct path loads are as follows: An … external table load attempts to load datafiles
External Table Restrictions → external table does not describe any data that is stored in the database. An external table does … external table. This guarantees a consistent result set for all queries. However, for performance reasons … you can decide to process only the referenced columns of an external
Datatype Conversion During External Table Use → When data is moved into or out of an external table, it is possible that the same column will have … data is unloaded into an external table and it is the destination when data is loaded from an external … table. The external table: When data is unloaded
Creating External Tables → You create external tables using the ORGANIZATION EXTERNAL clause of the CREATE TABLE statement … . You are not in fact creating a table; that is, an external table does not have any extents associated … external data. The following example creates an external
Managing External Tables → is provided. By providing the database with metadata describing an external table, the database is … able to expose the data in the external table as if it were data residing in a regular database table … , join, or sort external table data. You can also create views
Altering External Tables → external table. No other clauses are permitted. Table 15-3 ALTER TABLE Clauses for External Tables … column list from the same external table. This is the default. PROJECT COLUMN ALL: the access driver … processes all of the columns defined on the external
Dropping External Tables → For an external table, the DROP TABLE statement removes only the table metadata in the database. It
Conventional Path Loads, Direct Path Loads, and External Table Loads → SQL*Loader provides the following methods to load data: Conventional Path Loads Direct Path Loads External Table Loads
Example: Creating and Loading an External Table Using ORACLE_LOADER → load an external table. A traditional table named emp is defined along with an external table named … emp_load. The external data is then loaded into an internal table. Assume your.dat file looks as … ); Create an external table named
External Tables → External tables let you use external data as a virtual table that can be queried and joined … -path INSERT AS SELECT statement in conjunction with the SELECT from an external table. Figure 16-4 … directly and in parallel without requiring the external data to be first loaded in the database.
External Tables → not compatible with files created when you manually create an external table using the SQL CREATE … TABLE... ORGANIZATION EXTERNAL statement. One of the reasons for this is that a manually created … external table unloads only data (no metadata), whereas Data Pump maintains both data
External Tables → External tables access data in external sources as if it were in a table in the database. You can … connect to the database and create metadata for the external table using DDL. The DDL for an external … external table does not describe any data that
Overview of External Tables → access data in external sources as if it were in a table in the database. External tables can be written … index creation are allowed on an external table. Therefore, SQL*Loader may be the better choice in … data loading situations that require additional indexing of the staging table.
12 External Tables Concepts → access data in external sources as if it were in a table in the database. Prior to Oracle Database … additional indexing of the staging table. See Behavior Differences Between SQL*Loader and External … in text format. You must also know enough about SQL to be able to create an external table
Syntax and Datatypes → The following are not supported with external table loads: Use of CONTINUEIF or CONCATENATE to … datatypes: GRAPHIC, GRAPHIC EXTERNAL, and VARGRAPHIC Use of the following database column types: LONG s
Using External Tables to Load and Unload Data → from a table in the database and inserting it into an external table. Note: Data can only be unloaded using the ORACLE_DATAPUMP access driver. … In the context of external tables, loading data refers to the act of reading data from an external … table and loading it into a table
How Are External Tables Created? → External tables are created using the SQL CREATE TABLE...ORGANIZATION EXTERNAL statement. When you … create an external table, you specify the following attributes: TYPE - specifies the type of … external table. The two available types are the ORACLE_LOADER type and
Parallel Access to External Tables → To enable external table support of parallel processing on the datafiles, use the PARALLEL clause … when you create the external table. Each access driver supports parallel access slightly differently.
Performance Hints When Using External Tables → Performance Hints When Using External Table s When you monitor performance, the most important … global area (SGA). For this reason, you should be careful when using external tables on shared servers