Managing Db2 Metadata

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.

• If you select Aliases as a filtering option and the Alias points to a Remote Db2 system, it must be Version 8 or higher. Only one level of Remote Db2 is supported.
• If you select Nicknames as a filtering option on platforms where Db2 supports the Nickname object type (Windows and UNIX), a basic synonym is created for this type of Db2 object; no Titles, Remarks, or Keys are recorded in the synonym. The user ID who creates the synonym must have SELECT authority for this object type.

Important: If you select Stored Procedures as your object type, the input parameters will be a little different from those described here. For details, see Reporting Against a Db2 Stored Procedure.

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.

Note: All platforms except IBM i.

Filter by Library/Object Name (IBM i)

To avoid the return of an extremely large and potentially unmanageable list, always supply a value for Library or Object Name:

• Library. Type a string for filtering the Library (or Db2 Collection), 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 IDs begin with the letters ABC; %ABC to select tables or views whose owner IDs end with the letters ABC; %ABC% to select tables or views whose owner IDs contain the letters ABC at the beginning, middle, or end.
• Object name. Type a string for filtering the table, view, or object names, inserting the wildcard character (%) as needed at the beginning and/or end of the string. For example, enter: ABC% to select all tables, views, or 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.

Note: When you create a synonym for Db2 on the IBM i platform, standard IBM i naming conventions apply to the target data source. Therefore, the Adapter for Db2 supports the use of double-quotation marks around any library name and/or file name that contains lowercase or NLS characters.

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 WebFOCUSWeb Query 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.

Build cluster using foreign keys (deprecated)

You can select the Build cluster using foreign keys check box to include within this synonym every table related to the current table by a foreign key. However, this option has been deprecated, as the recommended way to create a cluster is by using the Synonym Editor. The resulting multi-table synonym describes all of the foreign key relationships of this table.

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 has valid syntax that can be used in the FROM statement of the generated SQL (what is known as a Derived Table), then the SQL SCRIPT will be processed as a subquery embedded into a FROM clause. This usage allows for more flexibility. For example, the synonym can be used as a target for a JOIN.

If the SQL SCRIPT has parameter markers, such as ? or :, or the syntax contains constructs that are invalid for a derived table, for example ORDER BY, then this keyword should not be selected. At runtime, if SUBQUERY=Y is present and it is determined that the SQL SCRIPT cannot be used in the FROM statement, 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.

Update or Create Metadata

Select Create to overwrite any existing synonym with the same fully-qualified name, or Update to synchronize the metadata with an existing synonym. If you select Update, the next screen will show a list of attributes from the DBMS catalog that you can check to allow attributes from the DBMS catalog to override attributes from the existing synonym.

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.

One-part name (IBM i)

On the IBM i platform, the One-part name check box is unchecked by default. The unchecked behavior generates a table name that includes the explicit name of the library containing the table. For example, if you specified a library on the first Create Synonym pane, a qualified name like the following is automatically created in the Access File for a TABLE or VIEW:

TABLENAME=MYLIB/MYTABLE

For a Stored Procedure, this would be a Db2 RPC and identified in the Access File as:

STPNAME=MYLIB/MYPROC

With this explicit type of entry in the Access File, at run-time the library is directly referenced and the object opened.

If you select the check box, the explicit library name is not stored in the metadata (Access File). When the synonym is generated, the library portion of the table name is omitted from the Access File, and appears as follows:

TABLENAME=MYTABLE

or

STPNAME=MYPROC

With this type of entry in the Access File (one-part name), the Db2 library search path will be used at run time. The exact composition varies depending on if Db2 is configured as a CLI or SQL connection.

For CLI configured servers, the search path will be the default library of Db2 for a CLI connected user (usually QSYS and QSYS2 plus the default library of the user). It is also controllable by use of a passthru command setting the path, such as SLQ DB2 SET PATH “QSYS”,”QSYS2”,”FOO”,”EXTRAFOO” as issued within a requests FOCEXCEC procedure or a profile. For SQL configured servers, the search path will be *LIBL. The library path of the process can be controlled by commands, such as ADDLIBLE, either before server start or as issued within a requests FOCEXCEC procedure or a profile.

Default Synonym Name

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

Select tables

Select tables for which you wish to create synonyms:

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

Table name

Is the name of the underlying object.

These mappings are OS-system specific:

Mapping Db2 Table Attributes

Mapping Db2 Column Attributes

This chart describes the keywords in the Access File.

SEGNAME

TABLENAME

TABLENAME=[location.][owner.]tablename

TABLENAME=[library/]tablename

CONNECTION

CONNECTION=connection

DBSPACE

datasource.tablespace 
DATABASE datasource

KEYS

KEY

KEY=fld1/fld2/.../fldn

WRITE

KEYFLD
IXFLD

AUTO
INCREMENT

START

INCREMENT

INDEX_NAME
INDEX_UNIQUE
INDEX_COLUMNS
INDEX_ORDER

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 available options.

For a list of options, see Synonym Management Options.

ENGINE DB2 SET VARCHAR {ON|OFF}

where:

DB2

Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.

ON

Maps the Db2 data type VARCHAR as variable-length alphanumeric (AnV). This is required for Unicode environments. ON is the default value.

OFF

Maps the Db2 data type VARCHAR as alphanumeric (A).

To activate this support, you must issue the following command in one of the supported server profiles

where:

DB2

Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.

BLOB

Activates long binary support. ALPHA is the default value.