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Part 4: correct projection of type tags in the outermost projector.

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This commit is contained in:
Richard Newman 2017-04-11 10:14:33 -07:00
parent d8075aa07d
commit bca8b7e322
1 changed files with 9 additions and 30 deletions
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39
query-projector/src/lib.rs
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@ -37,33 +37,18 @@ use mentat_db::{
use mentat_query::{
Element,
FindSpec,
Variable,
};
use mentat_query_algebrizer::{
AlgebraicQuery,
DatomsColumn,
QualifiedAlias,
/*
ConjoiningClauses,
DatomsTable,
SourceAlias,
*/
ColumnName,
VariableColumn,
};
use mentat_query_sql::{
ColumnOrExpression,
/*
Constraint,
FromClause,
*/
Name,
Projection,
ProjectedColumn,
/*
SelectQuery,
TableList,
*/
};
error_chain! {
@ -169,14 +154,6 @@ impl TypedIndex {
}
}
fn column_name(var: &Variable) -> Name {
var.to_string()
}
fn value_type_tag_name(var: &Variable) -> Name {
format!("{}_value_type_tag", var.as_str())
}
/// Walk an iterator of `Element`s, collecting projector templates and columns.
///
/// Returns a pair: the SQL projection (which should always be a `Projection::Columns`)
@ -213,7 +190,7 @@ fn project_elements<'a, I: IntoIterator<Item = &'a Element>>(
.expect("Every variable has a binding");
let qa = columns[0].clone();
let name = column_name(var);
let name = VariableColumn::Variable(var.clone()).column_name();
if let Some(t) = query.cc.known_type(var) {
cols.push(ProjectedColumn(ColumnOrExpression::Column(qa), name));
@ -221,15 +198,17 @@ fn project_elements<'a, I: IntoIterator<Item = &'a Element>>(
templates.push(TypedIndex::Known(i, tag));
i += 1; // We used one SQL column.
} else {
let table = qa.0.clone();
cols.push(ProjectedColumn(ColumnOrExpression::Column(qa), name));
templates.push(TypedIndex::Unknown(i, i + 1));
i += 2; // We used two SQL columns.
// Also project the type from the SQL query.
let type_name = value_type_tag_name(var);
let type_qa = QualifiedAlias::new(table, DatomsColumn::ValueTypeTag);
cols.push(ProjectedColumn(ColumnOrExpression::Column(type_qa), type_name));
let extracted_alias = query.cc
.extracted_types
.get(var)
.expect("Every variable has a known type or an extracted type");
let type_name = VariableColumn::VariableTypeTag(var.clone()).column_name();
cols.push(ProjectedColumn(ColumnOrExpression::Column(extracted_alias.clone()), type_name));
}
}
}