29 lines
1.1 KiB
Markdown
29 lines
1.1 KiB
Markdown
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Create overviews for vector dataset.
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#### Using the function
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The table for which overviews will be generated should be
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a Cartodbfied dataset with vector geometry.
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```sql
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SELECT CDB_CreateOverviews('table_name');
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--- Generates overview tables for the dataset
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```
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#### Arguments
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CDB_CreateOverviews(table_name, ref_z_strategy, reduction_strategy)
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* **table_name** regclass, table for which overviews will be generated
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* **ref_z_strategy** regproc, function that provides the Z-scale strategy.
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It returns the base Z level for the dataset.
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It should have these arguments:
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- **table_name** regclass, table to compute the reference Z scale for
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* **reduction_strategy** regproc, function that provides the reduction strategy
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to generate an overview table from a table for a smaller scale (higher Z number).
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It returns the name of the generated table.
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It should have these arguments:
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- **base_table_name** regclass, base table to be reduced.
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- **base_z** integer, base Z level assigned to the base table.
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- **overview_z** integer, Z level for which to generate the overview.
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