parquet_table_example Module

A worked example of a user-added table parameter, and the thing that makes this module's clone_extra/init_extra statements non-trivial: the generator writes out%zeropoint = self%zeropoint and self%zeropoint = 0.0_real64 from this declaration, and test/test_table_codegen.f90 checks that both happen.

Number of rows every column holds.

Number of columns the table has.

Copy out every column name, in order.

A column's 1-based position, 0 when absent.

Copy out the name at a 1-based position.

A resolved handle on one column, by name or by 1-based position. Resolves once -- the lookup, the lazy first touch and the kind -- so a per-element loop over that column stops paying for a name lookup on every access. See parquet_table_col.

Whether a column holds (or may hold) nulls -- named, or by 1-based position.

Copy out a column's validity as a plain logical array. A rank-1 mask gives one entry per row (on a *_VEC column: "any element of the row is null"); a rank-2 mask gives the true (width, nrows) per-element state.

Counter bumped by every structural change.

Whether a column of this name exists.

Which of these columns the table does NOT have, as a packed array (zero-size when it has them all). The non-aborting half of %require_columns.

Aborts unless the table has every one of these columns, naming EVERY missing one -- not just the first, which is what a hand-written loop reports.

A column's PK_* kind discriminator -- named, or by 1-based position.

A column's values-per-row (1 if scalar) -- named, or by 1-based position.

Copy out a column's unit string -- named, or by 1-based position.

A column's RES_* residency state -- named, or by 1-based position.

Whether row i of a column is null, or -- given e as well -- element e of it.

Whether the table has left its file behind.

Whether a column's type can be read -- named, or by 1-based position.

Copy out the file this table came from.

One key from the file's metadata.

Reads the named column(s) now, instead of on first touch. Required before a parallel region: a first touch inside one is a hard error, since it would mutate shared state.

The same call as %prefetch, under the name that pairs with %materialize_all. Reaching for the definitive-sounding %materialize_all when only a few columns are wanted reads the whole file, silently; %materialize(names) is the one to find first.

Read every column not yet read.

Re-read one column; force= to discard local edits.

Drop a column's VALUES; force= if it holds local edits.

Claim a column's values as the caller's own, or unclaim.

Whether a column is claimed as holding the caller's values.

Check every qc-declaring column, holding none.

Print what the table holds, to stdout.

Rows before filter=/sample_fraction=.

Rows in the row groups this table covers.

Row-group row ranges, this table's rows or the file's.

A handle on one row, for code that works a row at a time rather than a column at a time. The index is 1-based within THIS table -- in the slice regime, row 1 is the slice's first row, not the file's.

Copies the rows a parquet_slice selects into a freshly allocated array of the caller's own kind, widening on the way exactly as %get does.

Writes values into the rows a parquet_slice selects -- %get_slice's counterpart. The kind must match the column's exactly, and the array must have one value per selected row.

Points p at a column's storage: zero copy, writable, and the pointer kind must match the stored kind exactly (ask %kind first if you do not know it). A parquet_string_column pointer aliases a PK_STRING column's packed store: read it and edit its values in place, but do NOT change its length or element count through the pointer -- the column's own row count would no longer describe it.

Copies a column into a freshly allocated array of the caller's own kind.

Reads one row's value out of a column, widening into the caller's variable exactly as %get does -- the one-call form of r = t%row(i) then r%get(name, v). On a *_VEC column the value is that row's whole vector.

Writes one row's value in place. The kind must match the column's exactly (as %set does), and writing a value CLEARS that row's null -- use %set_null to put one back. On a *_VEC column the value is that row's whole vector.

Marks null: row i of a column, element e of row i, or every entry a logical mask marks .false..

Marks row i -- or, given e, element e of it -- valid without saying what its value is. Only useful when a value is already there or is about to be written; %set_element clears the null itself.

Drop a null bitmap that no longer has nulls.

Allocate validity storage up front, for concurrent nulling.

Remove a column; force= for a predefined one.

Change the name a column is looked up by.

Add a copy of a column, optionally of another kind.

Convert a column to another kind, in place.

Keep only the rows a mask selects.

Reorders rows by one or more key columns. Detaching.

Keeps only the n best rows, in key order. Detaching.

The row order the keys imply, without reordering anything. Unlike %sort_by the table stays attached, so this is how to read rows in an order while keeping the file.

The n best rows in order, by selection rather than a full sort. Also non-mutating.

Whether the rows are already in that order.

Removes the listed rows. A thin convenience over %filter_rows, and like it, detaching.

Keeps only the first n rows. Detaching, like every row-structural change.

Appends rows: a whole table's worth, or one row. Detaching, like every row-structural change. The bulk idiom is %clone_structure -> fill -> %append(batch).

Appends n all-null rows, to be filled in afterwards. Detaching.

Release capacity appends left behind.

Makes room for n rows in every resident column, so the appends that follow do not reallocate. %compact's counterpart; neither changes the row set, so neither detaches.

Makes room for n COLUMNS, so that the %add_column calls that follow relocate nothing and leave an outstanding %col pointer valid. See its own doc-comment for the guarantee.

Column slots allocated, or spare.

Independent deep copy of this table.

Empty table with the same columns.

Binds a generated type's predefined columns.

Blocks intrinsic assignment: the store lives behind a pointer, so a default b = a would leave two tables sharing one store and double-freeing it.

Opens a file and binds every predefined column.

Opens one contiguous row range of a file, binding the same columns %init does. There is no sort argument: a sort reorders rows across the whole file, so a slice could not be cut along it.

Builds this table in memory, with no file behind it: every predefined column is created empty, or with nrows all-null rows. The output-catalogue shape.

Resets/initializes YOUR components.

Copies this type's own components on %clone/%clone_structure. Mostly written for you.

Name of the object. (string) Copied out as a character array sized to the longest value present.

A string vector column, which has only the character copy-out form. (string, width 2) Copied out as a character array sized to the longest value present.