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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 Microsoft SQL Server ODBC data types.
How to: Reference: |
Synonyms define unique names (or aliases) for each Microsoft SQL Server ODBC 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.
The adapter supports the creation of metadata for certain types of MS SQL Native Synonyms. This feature is only available for Microsoft SQL Server versions 2012 or higher.
You can create metadata for Native Synonyms under the following conditions:
object_name, schema_name.object_name,
or
database_name.schema_name.object_name.
The following types of Native Synonyms are not supported:
server_name.database_name.schema_name.object_name
The Dynamic Columns (NOCOLS) and Cardinality (WITHSTATS) parameters are not supported when creating metadata for a Native Synonym.
Note that creating a synonym for a stored procedure is described with reporting against a stored procedure, in Generating a Synonym for a Stored Procedure.
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.
Important: If you select Stored Procedures as your object type, the input parameters will be a little different from those described here. For details, refer to Creating a Report Against a Stored Procedure.
To specify a database from which you can select a table or other object, do one of the following:
Before selecting a database, if Use current database is checked, uncheck it.
To specify the intended database, choose from the Select database drop-down menu, which shows all databases on the targeted instance of Microsoft SQL Server. Selecting Default Database will retain the database set during connection configuration. If Default Database was not set during configuration, the database assigned to the active login on the SQL Server will be used as the default.
Selecting this option adds the Owner/Schema and Object Name parameters to the screen.
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.
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.
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.
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).
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 Microsoft SQL Server ODBC Data Type Support.
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.
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.
Is the name of the underlying object.
Select tables for which you wish to create synonyms:
An Adapter for Microsoft SQL Server ODBC 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=MSODBC ,$ 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=edaqa.nf29004, CONNECTION=connmss, KEYS=1, WRITE=YES,$
When you generate a synonym for a Microsoft SQL table or view, the adapter maps comments as follows:
Both Unicode and non-Unicode comments are supported.
Also, MS SQL Server column title (if present) is mapped to the TITLE attribute in the Master File synonym.
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 Microsoft SQL Server table. The table name can be fully qualified as follows: TABLENAME=[[database.]owner.]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. Corresponds to the first n fields in the Master File segment. This attribute requires the columns that constitute the key to be described first in the Master File. See the KEY attribute below for information about specifying the key fields without having to describe them first in the Master File. |
KEY |
Specifies the columns that participate in the primary key without having to describe them first in the Master File. The syntax is: KEY=fld1/fld2/.../fldn |
WRITE |
Specifies whether write operations are allowed against the table. |
KEYFLD IXFLD |
Supply the names of the primary key and foreign key fields that implement the relationships established by the multi-table Master File. Together, KEYFLD and IXFLD identify the field shared by a related table pair.
KEYFLD and IXFLD must have the same data type. It is recommended, but not required, that their lengths also be the same. Note: An RDBMS index on both the KEYFLD and IXFLD columns provides the RDBMS with a greater opportunity to produce efficient joins. The columns must have the same data type. If their length is the same, the RDBMS handles the join more efficiently. |
AUTO INCREMENT |
When set to Yes, enables the auto increment feature. |
START |
Initial value in incrementing sequence. |
INCREMENT |
Increment interval. |
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). |
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. Drop Table. Drops the table so that it is removed from the DBMS. Insert Sample Data. Inserts specified number of sample records, populating all fields with counter values. Show/Modify Data. Opens a window that shows the data in the data source with buttons you can click to insert values, filter values, reload the data source, and customize the view. Reorganize. Recreates the data source table preserving original data. Note: This option is not available in the Web Console. |
Impact Analysis |
Generates a report showing where this synonym is stored and used, with links to the synonym instances. Impact Analysis reports enable you to evaluate changes before they are made by showing which components will be affected. See the Server Administration manual for details about Impact Analysis reports. |
Dependencies Analysis |
Generates a report showing information about the synonym and other synonyms and objects that are referenced within it. |
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. |
Privileges |
Shows the security subjects on the server and the privileges they have to this synonym. |
Properties |
Displays the properties of the synonym, including physical location, last modified date, description, and privileges. |
How to: |
SQL Data Type mapping options are available in a report available from the Web Console.
To access the Data Type Report:
The Filter Data Types Report page opens, as shown in the following image.
The Filter Data Types Report is displayed, as shown in the following image.
Note: You can also display the report as a PDF by selecting the Show Report in PDF check box.
The new SQL Expression generator in the TABLE Adapter by default preserves literal contents, including trailing blanks in string literals and the fractional part and exponential notation in numeric literals. This allows greater control over the generated SQL.
In some rare cases when trailing blanks are not needed, the following syntax
ENGINE MSODBC SET TRIM_LITERALS ON
is available to ensure backward compatibility.
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.
ENGINE MSODBC SET CONVERSION RESET ENGINE MSODBC SET CONVERSION format RESET ENGINE MSODBC SET CONVERSION format [PRECISION precision [scale]] ENGINE MSODBC SET CONVERSION format [PRECISION MAX]
where:
Indicates the adapter. You can omit this value if you previously issued the SET SQLENGINE command.
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.
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. 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.
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).
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).
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.
The following example shows how to set the precision attribute for all INTEGER and SMALLINT fields to 7:
ENGINE MSODBC 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 MSODBC 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 MSODBC SET CONVERSION INTEGER RESET
The following example shows how to set the precision and scale attributes for all fields to the defaults:
ENGINE MSODBC SET CONVERSION RESET
CREATE SYNONYM creates a field description with FIELDTYPE=R for Microsoft SQL Server columns created as TIMESTAMP or columns with the IDENTITY attribute. These fields are read-only. When executing a MAINTAIN or MODIFY procedure, the adapter suppresses all write operations against columns marked in the Master File with FIELDTYPE=R.
This example creates a table in which the first column has the IDENTITY property and the second column is a timestamp column:
CREATE TABLE TAB1 (idproptab int IDENTITY (1,1), timstmp timestamp)
CREATE SYNONYM generates the following Master File for this table:
FILE=TAB1, SUFFIX=MSODBC ,$ SEGNAME=TAB1, SEGTYPE=S0 ,$ FIELD=IDPROPTAB, idproptab, I11, I4, MISSING=OFF, FIELDTYPE=R ,$ FIELD=TIMSTMP, timstmp, A16, A16, MISSING=ON, FIELDTYPE=R ,$
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