Managing Excel 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 Excel data types.


Top of page

x
Identifying the Adapter

How to:

The SUFFIX attribute in the Master File identifies the adapter needed to interpret a request. Use the SUFFIX value SQLEXCEL to identify the Adapter for Excel.



x
Syntax: How to Identify the Adapter
FILE[NAME]=file, SUFFIX=SQLEXCEL [,$]

where:

file

Is the file name for the Master File. The file name should start with a letter and be representative of the table or view contents. The actual file must have a .mas extension, but the value for this attribute should not include the extension.

SQLEXCEL

Is the value for the adapter.


Top of page

x
Creating Synonyms

How to:

Reference:

x x

Synonyms define unique names (or aliases) for each Excel table or sheet 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.



x
Procedure: How to Create a Synonym

To create a synonym, you must have previously configured the adapter. You can create a synonym from the Web Console or the Data Management Console.

  1. From the Web Console's menu bar, click Adapters, then New, and then Synonym

    or

    From the Data Management Console, right-click an application directory, then select New, and then Synonym.

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

  2. Click a connection for the configured adapter (or double-click in the Data Management Console).

    The first of a series of synonym creation panes opens.

  3. Select a Workbook.

    The default is the workbook selected for the ODBC source.

  4. You can type in a different workbook name or click on the ellipsis (...). This opens the Select Excel Workbook dialogue with the workbook name entered selected.
  5. Click the up arrow to see a list of all the workbooks in the same directory as the selected workbook. Select another workbook from that directory, or continue to click on the up arrow and/or folders to find the directory where the workbook you want to use is located.
  6. When you have selected the workbook click OK.

    Object Name: Entering an object name, optionally using the wildcard % limits the list of tables that appears in the next screen to those that match this name.

  7. Click Next.

    The second synonym creation window opens.

  8. Enter values for the parameters required by the adapter as described in the synonym creation parameters reference.
  9. 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.



x
Reference: Synonym Creation Parameters for Excel

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

Workbook

Select a Workbook. The default is the workbook selected for the ODBC source.

You can type in a different workbook name or click on the ellipsis (...). This opens the Select Excel Workbook dialogue with the workbook name entered selected.

Filter by Object name

Selecting this option adds the Object Name parameters to the screen.

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.

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.

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.

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.

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.

The list of tables consists of:

  • Range names in the workbook.
  • Sheet names. These names have a $ at the end of the name.


Example: Sample Generated Synonym

An Adapter for Excel synonym comprises a Master File and an Access File. This is a synonym for the table nf29004.

Master File

FILENAME=ONHAND, SUFFIX=SQLEXCEL, $
  SEGMENT=ONHAND, SEGTYPE=S0, $
    FIELDNAME=PROD_NUM, ALIAS=Prod_Num, USAGE=A255V, ACTUAL=A255V,
      MISSING=ON, $
    FIELDNAME=PRODNAME, ALIAS=Prodname, USAGE=A255V, ACTUAL=A255V,
      MISSING=ON, $
    FIELDNAME=QTY_IN_STOCK, ALIAS=Qty_in_Stock, USAGE=D20.2, ACTUAL=D8,
      MISSING=ON, $
    FIELDNAME=PRICE, ALIAS=Price, USAGE=D20.2, ACTUAL=D8,
      MISSING=ON, $
    FIELDNAME=COST, ALIAS=Cost, USAGE=D20.2, ACTUAL=D8,
      MISSING=ON, $

Access File

SEGNAME=SEG1_4,TABLENAME=EDAQA.NF29004,
CONNECTION=DB1,KEYS=1,WRITE=YES,$


x
Reference: Access File Keywords

This chart describes the keywords in the Access File for Excel.

Keyword

Description

SEGNAME

Value must be identical to the SEGNAME value in the Master File.

TABLENAME

Identifies the Excel table. The value assigned to this attribute can include the name of the workbook as follows:

TABLENAME=[filename]table 
CONNECTION

Indicates a previously declared connection. The syntax is:

CONNECTION=connection

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.



x
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.



x
Data Type Support

Data types are specific to the underlying data source.


Top of page

x
Changing the Precision and Scale of Numeric Columns

How to:

You can alter the length and scale of numeric columns returned by a SELECT request to the server by creating different specifications in your login profile or in a stored procedure. The conversion settings are reflected in the Master File in the USAGE and ACTUAL formats of the fields generated by CREATE SYNONYM. This affects how the fields are processed and formatted by the server.

Tip: You can change this setting manually or from the Web Console.



x
Syntax: How to Override the Default Precision and Scale
x
ENGINE SQLEXCEL SET CONVERSION RESET
ENGINE SQLEXCEL SET CONVERSION format RESET
ENGINE SQLEXCEL SET CONVERSION format [PRECISION precision [scale]]
ENGINE SQLEXCEL SET CONVERSION format [PRECISION MAX]

where:

SQLEXCEL

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

RESET

Returns any previously specified precision and scale values to the adapter defaults. If you specify RESET immediately following the SET CONVERSION command, all data types return to the defaults. If you specify RESET following a particular data type, only columns of that data type are reset.

format

Is any valid format supported by the data source. Possible values are:

INTEGER which indicates that the command applies only to INTEGER columns.

DECIMAL which indicates that the command applies only to DECIMAL columns.

REAL which indicates that the command applies only to single-precision floating-point columns.

Note: Only applies to DB2, CA-IDMS/SQL, Microsoft SQL Server, and Sybase.

FLOAT which indicates that the command applies only to double-precision floating-point columns.

precision

Is the precision. Must be greater than 1 and less than or equal to the maximum allowable value for the data type (see the description of MAX).

scale

Is the scale. This is valid with DECIMAL, FLOAT and REAL data types. If you do not specify a value for scale, the current scale setting remains in effect. The default scale value is 2.

If the scale is not required, you must set the scale to 0 (zero).

MAX

Sets the precision to the maximum allowable value for the indicated data type:

Data Type

MAX Precision

INTEGER

11

DECIMAL

18

REAL

9

FLOAT

20

Note: When issuing the CREATE SYNONYM command while the CONVERSION command is active in the profile, the Master File reflects the scale and length that is set by the CONVERSION command.

However, when issuing a SELECT statement, the answer set description does not use the information in the Master File. The length and scale used for the answer set description depends on whether a CONVERSION command is in effect.

If a CONVERSION command is in effect, the answer set description uses the length and scale that is set by the CONVERSION command.

If a CONVERSION command is not in effect, the answer set description uses the actual length and scale of the data.



Example: Setting the Precision and Scale Attributes

The following example shows how to set the precision attribute for all INTEGER and SMALLINT fields to 7:

ENGINE SQLEXCEL SET CONVERSION INTEGER PRECISION 7

The following example shows how to set the precision attribute for all DOUBLE PRECISION fields to 14 and the scale attribute to 3:

ENGINE SQLEXCEL SET CONVERSION FLOAT PRECISION 14 3

The following example shows how to set the precision attribute for all INTEGER and SMALLINT fields to the default:

ENGINE SQLEXCEL SET CONVERSION INTEGER RESET

The following example shows how to set the precision and scale attributes for all fields to the defaults:

ENGINE SQLEXCEL SET CONVERSION RESET

iWay Software