Managing Rdb Metadata

In this section:

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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Creating Synonyms

How to:

Reference:

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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.



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Procedure: How to Create a Synonym

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.

  1. From the Web Console menu bar, click Applications.

    The Applications page opens.

  2. Click the New button and select Synonym from the drop-down menu.

    The Select adapter to configure or Select connection to create synonym pane opens.

  3. Click a connection for the configured adapter.

    The first of a series of synonym creation panes opens.

  4. Enter values for the parameters required by the adapter as described in the synonym creation parameters reference.
  5. After entering the parameter values, click Create Synonym.

    The Status pane indicates that the synonym was created successfully.

The synonym is created and added under the specified application directory.

Note:



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Reference: Synonym Creation Parameters for Rdb

The following list describes the synonym creation parameters for which you can supply values.

Restrict Object Type to

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.

Filter by Owner/Schema and Object name

Selecting this option adds the Owner/Schema and Object Name parameters to the screen.

  • Owner/Schema. Type a string for filtering the selection, inserting the wildcard character (%) as needed at the beginning and/or end of the string. For example, enter: ABC% to select tables or views whose owner/schema begin with the letters ABC; %ABC to select tables or views whose owner/schema end with the letters ABC; %ABC% to select tables or views whose owner/schema contain the letters ABC at the beginning, middle, or end.
  • Object name. Type a string for filtering the object names, inserting the wildcard character (%) as needed at the beginning and/or end of the string. For example, enter: ABC% to select all objects whose names begin with the letters ABC; %ABC to select all whose names end with the letters ABC; %ABC% to select all whose names contain the letters ABC at the beginning, middle, or end.
Location of External SQL Scripts

xIf 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:

  • In the Base Location field, specify the physical directory location of the file that contains the SQL Query. You can type a directory name or click on the ellipsis. This opens the Select Base Location dialog box.
  • In the Document Name field, enter the file name with or without wild card characters.
  • In the Document Extension field, enter the extension of the script files to filter the list of candidates.

On IBM i, you can use alternative IFS naming conventions to access library members. The following entry illustrates this method:

  • In the Base Location field, enter:
    /QSYS.LIB/MYLIBRARY.LIB/MYSRC.FILE
  • The Document Extension is understood to be MBR. You can enter this value explicitly or leave the input box blank.

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.

Cardinality

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.

Dynamic columns

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.

For Subquery

Only available when External SQL Scripts is selected from the Restrict objects type to drop-down menu. When selected, a SUBQUERY keyword is added to the Access File of the generated synonym. If the corresponding SQL string is not parameterized (that is, does not contain parameter markers, such as ? or :), it will be processed as a subquery embedded into a FROM clause of the generated SELECT query. Otherwise, the setting will be ignored, and a FOC1782 warning message will be issued. The default is selected (SUBQUERY=Y).

Application

Select an application directory. The default value is baseapp.

Prefix/Suffix

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.

Customize data type mappings

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.

Overwrite Existing Synonyms

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.

Default Synonym Name

This column displays the name that will be assigned to each synonym. To assign a different name, replace the displayed value.

Owner/Schema

The user account that created the object or a collection of objects owned by a user.

Type

The object type (Table, View, and so on).

Select tables

Select tables for which you wish to create synonyms:

  • To select all tables in the list, click the Select All button.
  • To select specific tables, select the corresponding check boxes.


Example: Sample Generated Synonym

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$HANDLE.NF29004',
CONNECTION=DSN_A,KEYS=1,WRITE=YES,$


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Reference: Access File Keywords

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.

INDEX_NAME
INDEX_UNIQUE
INDEX_COLUMNS
INDEX_ORDER

Indicate a name of the index in a database, uniqueness, name, and order of the indexed column(s).



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Reference: Managing Synonyms

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

Open

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 Open 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.

Reorganize. Recreates the data source table preserving original data.

Note: This option is not available in the Web Console.

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 the clipboard.

Delete

Deletes the synonym. You are asked to confirm this selection before the synonym is deleted.

Cut

Deletes the synonym and places it on the clipboard.

Properties

Displays the properties of the synonym, including physical location, last modified date, description, and privileges.



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Rdb Data Type Support
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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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