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When the server accesses a data source, it needs to know how to interpret the data stored there. For each data source the server will access, you create a synonym that describes the structure of the data source and the server mapping of the Rdb data types.
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Synonyms define unique names (or aliases) for each Rdb table or view that is accessible from the server. Synonyms are useful because they hide the underlying data source location and identity from client applications. They also provide support for extended metadata features of the server, such as virtual fields and additional security mechanisms.
Using synonyms allows an object to be moved or renamed while allowing client applications to continue functioning without modification. The only modification required is a redefinition of the synonym on the server. The result of creating a synonym is a Master File and an Access File, which represent the server metadata.
To create a synonym, you must have previously configured the adapter. You can create a synonym from the Applications or Adapters pages of the Web Console.
The Applications page opens.
The Select adapter to configure or Select connection to create synonym pane opens.
The first of a series of synonym creation panes opens.
The Status pane indicates that the synonym was created successfully.
The synonym is created and added under the specified application directory.
Note:
The following list describes the synonym creation parameters for which you can supply values.
Restrict candidates for synonym creation based on the selected object type(s): Tables, Views, External SQL Scripts, and any other supported objects.
Choosing External SQL Scripts from the drop-down list enables you to represent an SQL Query as a synonym for read-only reporting. A Synonym candidate can be any file that contains one (and only one) valid SQL Query and does not contain end-of-statement delimiters (";" or "/") and comments.
Depending on the adapter, you can further restrict your search by choosing check boxes for listed objects.
Selecting this option adds the Owner/Schema and Object Name parameters to the screen.
If you specify External SQL Scripts in the Restrict Object type to field, these additional fields are displayed.
The following standard naming conventions apply for UNIX, IBM i IFS, and z/OS HFS:
On IBM i, you can use alternative IFS naming conventions to access library members. The following entry illustrates this method:
/QSYS.LIB/MYLIBRARY.LIB/MYSRC.FILE
During synonym generation, the adapter issues native API calls to obtain a list of elements in the select list and builds the Master File with a field for each element. The generated Access File references the location of the SQL script in the DATASET attribute, which contains the full path, including the name and extension of the file containing the SQL Query. For example,
DATASET=/ul/home2/apps/report3.sql
When a WebFOCUS report is created, the SQL Query is used to access data.
Select the Cardinality check box to reflect the current cardinality (number of rows or tuples) in the table during metadata creation. Cardinality is used for equi-joins. The order of retrieval is based on the size (cardinality) of the table. Smaller tables are read first.
If the cardinality of the tables to be used in the application are dynamic, it may not be beneficial to choose this setting.
To specify that the Master File created for the synonym should not contain column information, select the Dynamic columns check box.
If this option is selected, column data is retrieved dynamically from the data source at the time of the request.
Select an application directory. The default value is baseapp.
If you have tables with identical table names, assign a prefix or a suffix to distinguish them. For example, if you have identically named human resources and payroll tables, assign the prefix HR to distinguish the synonyms for the human resources tables. Note that the resulting synonym name cannot exceed 64 characters.
If all tables and views have unique names, leave the prefix and suffix fields blank.
To change the data type mappings from their default settings, select this check box. The customizable mappings are displayed.
For information about customizable mappings, see Rdb Data Type Support.
To specify that this synonym should overwrite any earlier synonym with the same fully qualified name, select the Overwrite existing synonyms check box.
Note: The connected user must have operating system write privileges in order to recreate a synonym.
This column displays the name that will be assigned to each synonym. To assign a different name, replace the displayed value.
The user account that created the object or a collection of objects owned by a user.
The object type (Table, View, and so on).
Select tables for which you wish to create synonyms:
An Adapter for Rdb synonym comprises a Master File and an Access File. This is a synonym for the table nf29004.
Generated Master File nf29004.mas
FILE=DIVISION, SUFFIX=SQLRDB ,$ SEGNAME=SEG1_4, SEGTYPE=S0 ,$ FIELD=DIVISION4, DIVISION4, I9, I4, MISSING=OFF ,$ FIELD=DIVISION_NA4, DIVISION_NA4, A25, A25, MISSING=ON ,$ FIELD=DIVISION_HE4, DIVISION_HE4, I9, I4, MISSING=ON ,$
Generated Access File nf29004.acx
SEGNAME=SEG1_4,'TABLENAME=RDB$HANDLE.NF29004', CONNECTION=DSN_A,KEYS=1,WRITE=YES,$
This chart describes the keywords in the Access File.
Keyword |
Description |
---|---|
SEGNAME |
Value must be identical to the SEGNAME value in the Master File. |
TABLENAME |
Identifies the Rdb table. |
CONNECTION |
Indicates a previously declared connection. The syntax is: CONNECTION=connection CONNECTION=' ' indicates access to the local database server. Absence of the CONNECTION attribute indicates access to the default database server. |
KEYS |
Indicates how many columns constitute the primary key for the table. Range is 0 to 64. Corresponds to the first n fields in the Master File segment. |
WRITE |
Specifies whether write operations are allowed against the table. |
Once you have created a synonym, you can right-click the synonym name in the Adapter navigation pane of either the Web Console or the Data Management Console to access the following options.
Option |
Description |
---|---|
Edit |
Opens the Master File for viewing and editing using a graphical interface. If an Access file is used it will be also available. |
Edit as Text |
Enables you to view and manually edit the Master File synonym. Note: To update the synonym, it is strongly recommended that you use the graphical interface provided by the Edit option, rather than manually editing the Master File. |
Edit Access File as Text |
Enables you to view and manually edit the Access File synonym. Note: This option is available only when an Access File is created as part of the synonym. |
Sample Data |
Retrieves up to 20 rows from the associated data source. |
Data Profiling |
Data Profiling provides the data characteristics for synonym columns. Alphanumeric columns provide the count of distinct values, total count, maximum, minimum, average length, and number of nulls. Numeric columns provide the count of distinct values, total count, maximum, minimum, average value, and number of nulls. |
Refresh Synonym (if applicable) |
Regenerates the synonym. Use this option if the underlying object has been altered. |
Data Management |
Followed by these options, if applicable: Recreate DBMS Table. Recreates the data source table. You are asked to confirm this selection before the table is regenerated. (Note that the table will be dropped and recreated. During the process, data may be lost.) Delete All Data. Deletes all existing data. You are asked to confirm this selection before the data is deleted. Insert Sample Data. Inserts specified number of sample records, populating all fields with counter values. |
Impact Analysis |
Generates reports on procedures, synonyms, and columns that provide information on the flows/stored procedures available on a particular server, and the synonyms and columns they use. These reports enable you to evaluate changes before they are made by showing which components will be affected. See the Server Administration for UNIX, Windows, OpenVMS, IBM i, and z/OS manual for details about Impact Analysis Reports. |
Copy |
Copies the synonym to clipboard. |
Delete |
Deletes the synonym. You are asked to confirm this selection before the synonym is deleted. |
Cut |
Deletes the synonym and places it in clipboard. |
Properties |
Displays the properties of the synonym, including physical location, last modified date, and description. |
The following tables describe how the server maps Rdb data types.
Oracle Rdb Data Type |
Server Data Type |
Remarks | |
---|---|---|---|
USAGE |
ACTUAL | ||
Date-Time Data Types | |||
DATE ANSI |
A10 |
A10 |
|
DATE VMS |
A16 |
A16 |
|
TIME |
A8 |
A8 |
|
TIMESTAMP |
A22 |
A22 |
|
Numeric Data Types | |||
TINYINT (-128...127) |
I6 |
I4 |
|
SMALLINT (-32768... 32767) |
I6 |
I4 |
|
INTEGER (-231... 231 - 1) |
I11 |
I4 |
231 = 2,147,483,648. |
REAL |
D20.2 |
D8 |
32-bit FLOAT(n), where n is less than 25. |
DOUBLE PRECISION |
D20.2 |
D8 |
64-bit FLOAT(n), where n is 25 or greater. |
NUMERIC, DECIMAL (p,s) |
D20.2 |
D8 |
Same as REAL or DOUBLE PRECISION. 8 bytes; value range -2 * 10307 to2 * 10308. |
BIGINT (-263 ... 263 - 1) |
D20.2 |
D8 |
|
The following table lists how the server maps Character data types. This mapping can be changed based on the value of LONGCHAR. The default value is ALPHA.
Oracle Rdb Data Type |
Remarks |
LONGCHAR ALPHA |
LONGCHAR TEXT | ||
---|---|---|---|---|---|
USAGE |
ACTUAL |
USAGE |
ACTUAL | ||
CHAR (n) |
n is an integer between 1 and 256. |
An |
An |
An |
An |
n is an integer greater then 256. |
An |
An |
TX50 |
TX | |
VARCHAR (n) |
n is an integer between 1 and 256. |
AnV |
AnV |
AnV |
AnV |
n is an integer greater then 256. |
AnV |
AnV |
TX50 |
TX | |
LONGVARCHAR (n) |
n is an integer between 1 and 256. |
AnV |
AnV |
AnV |
AnV |
n is an integer greater then 256. |
AnV |
AnV |
TX50 |
TX |
Note: The main purpose of the LONGCHAR setting is to provide compatibility with previous releases of the server. This SET parameter was designed to control processing of DBMS Character data types and was never intended for DBMS LOB.
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