Modules, Windows And Dialogs > ER Diagram
The ER (Entity Relationship) diagrammer lets you quickly model a table and graphically see the dependencies and joins to other tables.
ER Diagram Toolbar
ER Diagram Display Area
For each table in the model
|The name of the table and schema it resides.
|The columns in the table, the column type, whether the column is indexed, and icons as applicable and selected in Create ER Diagram.
|Lines connect tables that are dependent on each other. Lines have a knob end and an arrow end. The referencing table resides at the knob end, and the referenced table at the arrow end.
To add tables to the diagram
Create ER Diagram
Modules, Windows And Dialogs > ER Diagram > Create ER Diagram
|Select the Schema where the table resides.
|Select the table to diagram.
How many levels of referential tables do you want to load?
Select as appropriate.
The more levels of referential tables you load, the more complicated the diagram will become, and the longer SQL Navigator will take to create the diagram.
- Show primary keys
- Show foreign keys
- Show unique keys
- Show data type
- Show not nullable
- Show indexes
If the display option has an icon associated with it, the icon is displayed to the right of the option. In the diagram, the appropriate icon will appear to the left of the table name.
Explain Plan Tool
Modules, Windows And Dialogs > Explain Plan Tool
Use the Explain Plan tool to analyze the execution of a single SQL statement. By examining the execution plan, you can see exactly how Oracle executes your SQL statement, and how it can be improved.
This tool lets you:
- generate plans and save them in the table of your choice
- organize your saved plans by various criteria, such as type (for example, online SQL statements, batch SQL statements, and so on), module, or subsystem
- build separate plan tables for different subsystems in your project
- browse each table separately.
TIP: The Analyze Tool can be used in conjunction with the Explain Plan tool. The Explain Plan Tool does not analyze tables itself prior to executing the Explain Plan, but it does have a toolbar button for manual launch of the Analyze Tool.
Explain Plan Window
Drag a SQL Statement into the editor on this tab.
|If required, you can enter a Statement ID to identify the statement within the current plan table.
|Save SQL text
|Select to save the SQL when saving the generated plan.
|Optionally, comment on the plan.
|Plan Table Owner
|Enter the Plan Table Owner or use the default listed.
Enter the Plan Table Name or use the default listed.
TIP: If specifying a new plan table, use the Create Table button to create the table.
|Click to view the Oracle execution plan for the statement.
|Browse Saved Plans
|Browse previously saved execution plans.
Explain the node selected in the Explain Plan tree. Show how each SQL operation is executed in relation in the Explain Plan.
Show / Hide in Generate Plans | Show Description.
|The generated execution plan. Click on nodes to expand and collapse them.
Print the Explain Plan tree
Use File | Print.
The following data is printed:
- The SQL Statement from which the explain plan tree was derived
- Statement ID, Type, Cost and Time stamp
- The Explain Plan tree, including the execution sequence numbers in brackets
- When the printout exceeds one page, the headings (such as the SQL Text and statement ID lines) are not repeated. This makes it easy for you to 'tile' multiple pages together to display the explain plan tree as a single diagram.
- Use File | Print Preview to preview your output.
Modules, Windows And Dialogs > Export Table
Open the Export Tables window
Open the Export Tables window from Object Menu | Export Table.
Select the tables to export (1)
In the Export Tables window, tables in the Selected Tables list are exported.
Ways to move tables to this list (from the Browse Table to Export list):
- Double-click on a table.
- Selecting one or more tables and click >.
- Select one or more schemas and click >. This adds all tables in the selected schemas.
- Click >>. This adds all tables in all schemas.
- Select objects before you open the Export Tables window.
Select export options (2)
Objects to export
Select the objects you want exported from the database to the DMP file.
Data is extracted directly, bypassing the SQL Command-processing layer. This method may be faster that a conventional path export.
Uses the SET TRANSACTION READ ONLY statement to ensure the data does not change during the execution of the export command.
Select this parameter if you anticipate other applications will update the data after an export has started.
Note: Tables are usually exported in a single transaction. However, nested and partitioned tables may be exported as separate transactions. If nested or partitioned tables are being updated by other applications, the exported data may be inconsistent. To minimize this possibility without selecting the Consistent parameter, export those tables at a time when updates are not being performed.
Records an incremental or cumulative export in the system tables SYS.INCEXP, SYS.INCFIL, and SYS.INCVID.
|Flags table data for consolidation into one initial extent upon import. If extent sizes are large (for example, because of the PCTINCREASE parameter), the allocated space will be larger than the space required to hold the data.
|Export uses the current storage parameters, including the values of initial extent size and next extent size. The values of the parameters may be the values specified in the CREATE TABLE or ALTER TABLE statements or the values modified by the database system. For example, the NEXT extent size value may be modified if the table grows and if the PCTINCREASE parameter is nonzero.
- Although the actual consolidation is performed upon import, you can specify the COMPRESS parameter only when you export, not when you import. The Export utility, not the Import utility, generates the data definitions, including the storage parameter definitions. Therefore, if you do not select Compress when you export, you can import the data in consolidated form only.
- Neither LOB data nor subpartition data is compressed. Rather, values of initial extent size and next extent size at the time of export are used.
Buffer size (leave blank for default)
The size, in bytes, of the buffer used to fetch rows. This parameter determines the maximum number of rows in an array fetched by Export.
Use the following formula to calculate the buffer size:
buffer_size = rows_in_array * maximum_row_size
If you specify zero, Export Tables fetches only one row at a time.
Tables with columns of type LOBs, LONG, BFILE, REF, ROWID, LOGICAL ROWID, or DATE are fetched one row at a time.
Note: See your Oracle operating system-specific documentation to determine the default value for this parameter.
The length, in bytes, of the file record. The RECORDLENGTH parameter is necessary when you must transfer the export file to another operating system that uses a different default value.
If you do not define this parameter, it defaults to your platform-dependent value for buffer size.
You can set RECORDLENGTH to any value equal to or greater than your system's buffer size. (The highest value is 64 KB.)
Changing the RECORDLENGTH parameter affects only the size of data that accumulates before writing to the disk. It does not affect the operating system file block size.
You can use this parameter to specify the size of the Export I/O buffer.
Note: See your Oracle operating system-specific documentation to determine the proper value or how to create a file with a different record size.
Select the type of database optimizer statistics to generate when the exported data is imported.
Provide a feedback dot each time n rows are exported
Export should display a progress meter in the form of a period for n number of rows exported.
For example, if you specify FEEDBACK=10, Export displays a period each time 10 rows are exported.
Note: The FEEDBACK value applies to all tables being exported; it cannot be set individually for each table.
Output file name (.dmp)
The names of the export dump files.
This field is mandatory.
Parameter file name (.dat)
A name for the file that contains a list of import parameters.
This field is mandatory.
Log file name (.log)
The name of the log file.
All informational and error messages are written to the log file.
When execution is complete there are three tabs in the Export Tables window. The results of the export are shown on the Output tab. The Log and Parameter file tabs show the contents of their respective files.