Example of How to Execute a Sample XML File

The sample XML and data files are provided under file_path\PSQL\samples\cobolschemaexec. For default locations of Pervasive PSQL files, see Where are the Pervasive PSQL files installed? in Getting Started With Pervasive PSQL.

To execute the XML file SampleMainTable.xml using Schema Executor perform the following steps.

Copy maintbl.mkd to the data file folder of the database to which you wish to connect.

For example, suppose that database "test" exists with a data file location of c:\data\test. Copy maintbl.mkd to c:\data\test.

Open a command prompt at the PSQL\bin\ directory .

Execute the following command at a DOS prompt:

cobolschemaexec file_path\PSQL\samples\cobolschemaexec\samplemaintable.xml test

On successful execution of Schema Executor, the table maintbl (as specified in the XML file) is created in the "test" database.

You man now perform SQL operations on table maintbl using PCC.

Additional Notes

This section provides notes pertaining to SELECT statements and table filters.

SELECT Statements

A SELECT query on an OCCURS table returns the following:

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the columns of the OCCURS table

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the column of the main table that comprises the mapping index

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an OCCURS counter that indicates the number of occurrences of the OCCURS clause.

For example, you perform the query SELECT * FROM FIELD for the tables created by the execution of Schema Executor on the sample XML file file_path\PSQL\samples\cobolschemaexec\ SampleMainWithOccurs.xml.

The utility returns columns Id, OccursCounter, Field_1, Field_2 and Field_3

A SELECT query on a REDEFINES table returns all of the columns of the parent table and the columns of the REDEFINES table.

For example, you perform the query SELECT * FROM Redefined_group for the tables created by the execution of Schema Executor on the sample XML file file_path\PSQL\samples\ cobolschemaexec\SampleMainWithRedefines.xml.

The utility returns columns Id, Account_Num, Category, Redef_Struct_Num (all columns of the parent table), Redefined_field_1 (column of the REDEFINES table).

Table Filters

A table filter (referred to as “TABLEFILTER” in the sample XML files) is a filter condition for a particular table.

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A TABLEFILTER may have an expression with left and right operands both being column names. For example, Cust_Num = My_Cust_Num (where both Cust_Num and My_Cust_Num are column names).

Provide a blank space between operands and the operator.

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If a constant value is used in the expression for a TABLEFILTER, the value must be specified within single quotes.

Example: Cust_Num = '100' (where Cust_Num is the column name)

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Use the following XML entities when specifying a TABLEFILTER in an XML file:


XML Entity	Used For
<	less than (<)
>	greater than (>)
&	ampersand (&) (AND)
"	double quotes (")
'	single quotes (')

Examples of valid TABLEFILTERs:

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Cust_Num = '100' (equivalent to Cust_Num = 100)

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Cust_Num < '100' (equivalent to Cust_Num < 100)

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Cust_Num > '100' (equivalent to Cust_Num > 100)

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Cust_Num <> '100' (equivalent to Cust_Num <> 100)

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'a' = Category | Account_Num <= 'a123' (equivalent to 'a'=category OR account_num <= 'a123')

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'a' = Category & Account_Num = 'a123' (equivalent to 'a' = category AND account_num = 'a123')

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Cust_Num = My_cust_Num (where both the operands are column names)