Virtual tables can be considered a collection of a complex type or, more precisely, as a reflection of an SQL table in memory.

1 Declaration of a Virtual Table

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<xsql-script>
    <body>
        <vtable name='v_update1'>
            <column name='delega'    type='string'  size='10' unique='true' />
            <column name='depart'    type='string'            unique='true' />
            <column name='numope'    type='smallint'  />
            <column name='import'    type='decimal' size='12' scale='3' />
        </vtable>

        <set name='v_update2'>
            <vtable.clone name='v_update1' />
        </set>

        <vtable.insert name='v_update1'>
            <matrix>
                { 'D01', 'COM', '1', '1000.25' },
                { 'D02', 'COM', '2', '400'     },
                { 'D03', 'VEN', '3', '700.75'  },
                { 'D04', 'ABC', '4', '200.0'   }
            </matrix>
        </vtable.insert>

        <vtable.insert name='v_update2'>
            <matrix>
                { 'D01', 'COM', '1', '1000.25' },
                { 'D02', 'COM', '2', '400'     },
                { 'D03', 'VEN', '3', '700.75'  },
                { 'D04', 'ABC', '4', '1000.0'  }
            </matrix>
        </vtable.insert>

        <println>table 1:<v_update1 /></println>
        <println>table 2:<v_update2 /></println>

        <vtable.update name='v_update1' where='delega="D04"'>
            <column name='import'><number>1000</number></column>
        </vtable.update>

        <println>Updated table 1:<v_update1 /></println>

        <assert>
            <expr><vtable.equals><v_update1 /><v_update2 /></vtable.equals></expr>
        </assert>
    </body>
</xsql-script>
table 1:
+------+------+------+--------+
|delega|depart|numope|import  |
+------+------+------+--------+
|D01   |COM   |     1|1000.250|
|D02   |COM   |     2| 400.000|
|D03   |VEN   |     3| 700.750|
|D04   |ABC   |     4| 200.000|
+------+------+------+--------+

table 2:
+------+------+------+--------+
|delega|depart|numope|import  |
+------+------+------+--------+
|D01   |COM   |     1|1000.250|
|D02   |COM   |     2| 400.000|
|D03   |VEN   |     3| 700.750|
|D04   |ABC   |     4|1000.000|
+------+------+------+--------+

Updated tabke1:
+------+------+------+--------+
|delega|depart|numope|import  |
+------+------+------+--------+
|D01   |COM   |     1|1000.250|
|D02   |COM   |     2| 400.000|
|D03   |VEN   |     3| 700.750|
|D04   |ABC   |     4|1000.000|
+------+------+------+--------+

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