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For a more detail version of this text see docs/readme.firebirdarrays.html |
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Example applications are provided for both one and two dimensional arrays. In each case, |
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the example applications create their own database and populate it with test data when |
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first run. Note that you will typically need to run the application before accessing |
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database properties in the IDE. This is in order to create the database referenced by the IDE. |
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Database Creation |
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----------------- |
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The IBDatabase property “CreateIfNotExists” is set to true in both examples. This |
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means that if the database does not exist when an attempt is made to connect to |
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it then the database is created. After it is created, the “OnCreateDatabase” |
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event handler is used to add a table to the newly created database and to |
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populate it with test data. The application then continues as if the database already existed. |
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By default, the database is created in the defined temporary directory. This |
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behaviour can be overridden by editing the example's “unit1” unit to remove |
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the “{$DEFINE LOCALDATABASE}” directive and setting the const “sDatabaseName” |
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to the required path e.g. |
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|
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const |
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sDatabaseName = 'myserver:/databases/test.fdb'; |
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1D Array Example |
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---------------- |
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In this case, the test data table is defined as |
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Create Table TestData ( |
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RowID Integer not null, |
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Title VarChar(32) Character Set UTF8, |
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MyArray Double Precision [1:12], |
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Primary Key(RowID) |
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); |
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Each row includes a floating point array with twelve elements. In the |
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example application, the table is displayed and edited using a DBControlGrid. |
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The title field is interpreted as a “Department” and displayed using a |
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TDBEdit control. The array field is interpreted as sales by month and |
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displayed as a one dimensional TIBArrayGrid with column labels. The |
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example allows both the Departname Name and monthly sales values |
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to be updated and changes saved. New rows can be inserted and |
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existing rows deleted. |
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Note: there is an LCL bug (http://bugs.freepascal.org/view.php?id=30892) which |
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will cause the 1D array example to render incorrectly. That is only the |
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focused row will show the array. The bug report includes an LCL |
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patch to fix this problem. |
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2D Array Example |
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---------------- |
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In this case, the test data table is defined as |
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|
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Create Table TestData ( |
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RowID Integer not null, |
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Title VarChar(32) Character Set UTF8, |
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MyArray VarChar(16) [0:16, -1:7] Character Set UTF8, |
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Primary Key(RowID) |
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); |
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Each row includes a two dimensional string array with indices 0..16 and -1 to 7. |
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The grid interprets the first index as a column index and the second as a row |
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index (i.e. x,y Cartesian co-ordinates). |
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The example program displays a row at a time with a navigation bar |
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providing the means to scroll through the dataset, as well as saving |
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or cancelling changes, inserting and deleting rows. |
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This example illustrates the use of both column and row labels. |
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