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Platform-independent, interactive-speed data analytics system
/*
* Copyright 2018 University of Michigan
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.verdictdb.sqlreader;
import org.verdictdb.core.sqlobject.*;
import org.verdictdb.parser.VerdictSQLParser;
import org.verdictdb.parser.VerdictSQLParserBaseVisitor;
import java.util.ArrayList;
import java.util.List;
public class RelationGen extends VerdictSQLParserBaseVisitor {
// private MetaData meta;
private List selectElems = new ArrayList<>();
// public RelationGen(MetaData meta) {
// this.meta = meta;
// }
public RelationGen() {}
@Override
public SelectQuery visitSelect_statement(VerdictSQLParser.Select_statementContext ctx) {
SelectQuery sel = (SelectQuery) visit(ctx.query_expression());
if (ctx.order_by_clause() != null) {
for (VerdictSQLParser.Order_by_expressionContext o :
ctx.order_by_clause().order_by_expression()) {
ExpressionGen g = new ExpressionGen();
UnnamedColumn c = g.visit(o.expression());
OrderbyAttribute orderbyCol = new OrderbyAttribute(c, (o.DESC() == null) ? "asc" : "desc");
sel.addOrderby(orderbyCol);
}
}
if (ctx.limit_clause() != null) {
sel.addLimit(ConstantColumn.valueOf(ctx.limit_clause().number().getText()));
}
return sel;
}
@Override
public AbstractRelation visitQuery_expression(VerdictSQLParser.Query_expressionContext ctx) {
AbstractRelation r = null;
if (ctx.query_specification() != null) {
r = this.visit(ctx.query_specification());
} else if (ctx.query_expression() != null) {
r = this.visit(ctx.query_expression());
}
/*
for (VerdictSQLParser.UnionContext union : ctx.union()) {
AbstractRelation other = this.visit(union);
SetRelation.SetType type;
if (union.UNION() != null) {
type = SetRelation.SetType.UNION;
if (union.ALL() != null) {
type = SetRelation.SetType.UNION_ALL;
}
} else if (union.EXCEPT() != null) {
type = SetRelation.SetType.EXCEPT;
} else if (union.INTERSECT() != null) {
type = SetRelation.SetType.INTERSECT;
} else {
type = SetRelation.SetType.UNKNOWN;
}
r = new SetRelation(vc, r, other, type);
}
*/
return r;
}
/**
* Parses a depth-one select statement. If there exist subqueries, this function will be called
* recursively.
*/
@Override
public AbstractRelation visitQuery_specification(
VerdictSQLParser.Query_specificationContext ctx) {
class SelectListExtractor extends VerdictSQLParserBaseVisitor> {
@Override
public List visitSelect_list(VerdictSQLParser.Select_listContext ctx) {
List selectList = new ArrayList<>();
for (VerdictSQLParser.Select_list_elemContext a : ctx.select_list_elem()) {
VerdictSQLParserBaseVisitor v =
new VerdictSQLParserBaseVisitor() {
@Override
public SelectItem visitSelect_list_elem(
VerdictSQLParser.Select_list_elemContext ctx) {
SelectItem elem = null;
if (ctx.STAR() != null) {
if (ctx.table_name() == null) {
elem = new AsteriskColumn();
} else {
elem = new AsteriskColumn(stripQuote(ctx.table_name().getText()));
}
} else {
ExpressionGen g = new ExpressionGen();
elem = g.visit(ctx.expression());
if (elem instanceof BaseColumn) {
if (ctx.column_alias() != null) {
elem = new AliasedColumn((BaseColumn) elem, ctx.column_alias().getText());
}
} else if (elem instanceof ColumnOp) {
if (ctx.column_alias() != null) {
elem = new AliasedColumn((ColumnOp) elem, ctx.column_alias().getText());
}
} else if (elem instanceof ConstantColumn) {
if (ctx.column_alias() != null) {
elem =
new AliasedColumn((ConstantColumn) elem, ctx.column_alias().getText());
}
}
}
return elem;
}
};
SelectItem e = v.visit(a);
selectList.add(e);
}
return selectList;
}
}
List tableSources =
new ArrayList<>(); // assume that only the first entry can be JoinedRelation
for (VerdictSQLParser.Table_sourceContext s : ctx.table_source()) {
AbstractRelation r1 = this.visit(s);
tableSources.add(r1);
}
// parse the where clause;
UnnamedColumn where = null;
if (ctx.WHERE() != null) {
CondGen g = new CondGen();
where = g.visit(ctx.where);
}
// parse select list
SelectListExtractor select = new SelectListExtractor();
List elems = select.visit(ctx.select_list());
selectElems = elems; // used in visitSelect_statement()
SelectQuery sel = SelectQuery.create(selectElems, tableSources);
if (where != null) {
sel.addFilterByAnd(where);
}
if (ctx.GROUP() != null) {
List groupby = new ArrayList();
for (VerdictSQLParser.Group_by_itemContext g : ctx.group_by_item()) {
GroupingAttribute gexpr = null;
ExpressionGen expressionGen = new ExpressionGen();
UnnamedColumn c = expressionGen.visit(g);
gexpr = c;
boolean aliasFound = false;
if (!aliasFound) {
groupby.add(gexpr);
}
}
if (!groupby.isEmpty()) {
sel.addGroupby(groupby);
}
}
UnnamedColumn having = null;
if (ctx.HAVING() != null) {
CondGen g = new CondGen();
having = g.visit(ctx.having);
}
if (having != null) {
sel.addHavingByAnd(having);
}
return sel;
}
private UnnamedColumn joinCond = null;
private JoinTable.JoinType joinType = null;
@Override
public AbstractRelation visitTable_source(VerdictSQLParser.Table_sourceContext ctx) {
return visitTable_source_item_joined(ctx.table_source_item_joined());
}
@Override
public AbstractRelation visitTable_source_item_joined(
VerdictSQLParser.Table_source_item_joinedContext ctx) {
AbstractRelation r = this.visit(ctx.table_source_item());
if (ctx.join_part().isEmpty()) {
return r;
}
JoinTable jr =
JoinTable.createBase(
r, new ArrayList(), new ArrayList());
// join error location: r2 is null
for (VerdictSQLParser.Join_partContext j : ctx.join_part()) {
AbstractRelation r2 = visit(j);
jr.addJoinTable(r2, joinType, joinCond);
}
return jr;
}
@Override
public AbstractRelation visitJoin_part(VerdictSQLParser.Join_partContext ctx) {
if (ctx.INNER() != null) {
AbstractRelation r = this.visit(ctx.table_source());
CondGen g = new CondGen();
UnnamedColumn cond = g.visit(ctx.search_condition());
joinType = JoinTable.JoinType.inner;
joinCond = cond;
return r;
} else if (ctx.LEFT() != null) {
AbstractRelation r = this.visit(ctx.table_source());
CondGen g = new CondGen();
UnnamedColumn cond = g.visit(ctx.search_condition());
joinType = JoinTable.JoinType.leftouter;
joinCond = cond;
return r;
} else if (ctx.RIGHT() != null) {
AbstractRelation r = this.visit(ctx.table_source());
CondGen g = new CondGen();
UnnamedColumn cond = g.visit(ctx.search_condition());
joinType = JoinTable.JoinType.rightouter;
joinCond = cond;
return r;
} else if (ctx.CROSS() != null) {
AbstractRelation r = this.visit(ctx.table_source());
joinType = JoinTable.JoinType.cross;
joinCond = null;
return r;
} else {
AbstractRelation r = this.visit(ctx.table_source());
CondGen g = new CondGen();
if (ctx.search_condition() != null) {
UnnamedColumn cond = g.visit(ctx.search_condition());
joinType = JoinTable.JoinType.inner;
joinCond = cond;
} else {
joinType = JoinTable.JoinType.cross;
joinCond = null;
}
return r;
}
}
private String stripQuote(String expr) {
return expr.replace("\"", "").replace("`", "");
}
@Override
public AbstractRelation visitHinted_table_name_item(
VerdictSQLParser.Hinted_table_name_itemContext ctx) {
AbstractRelation r = null;
if (ctx.as_table_alias() != null) {
if (ctx.table_name_with_hint().table_name().schema != null) {
r =
new BaseTable(
stripQuote(ctx.table_name_with_hint().table_name().schema.getText()),
stripQuote(ctx.table_name_with_hint().table_name().table.getText()),
stripQuote(ctx.as_table_alias().table_alias().getText()));
} else {
r =
BaseTable.getBaseTableWithoutSchema(
stripQuote(ctx.table_name_with_hint().table_name().table.getText()),
stripQuote(ctx.as_table_alias().table_alias().getText()));
}
} else {
if (ctx.table_name_with_hint().table_name().schema != null) {
r =
new BaseTable(
stripQuote(ctx.table_name_with_hint().table_name().schema.getText()),
stripQuote(ctx.table_name_with_hint().table_name().table.getText()));
} else {
r = new BaseTable(stripQuote(ctx.table_name_with_hint().table_name().table.getText()));
}
}
return r;
}
@Override
public AbstractRelation visitDerived_table_source_item(
VerdictSQLParser.Derived_table_source_itemContext ctx) {
RelationGen gen = new RelationGen();
SelectQuery r = (SelectQuery) gen.visit(ctx.derived_table().subquery().select_statement());
if (ctx.as_table_alias() != null) {
r.setAliasName(ctx.as_table_alias().table_alias().getText());
}
if (ctx.column_alias_list() != null) {
for (int i = 0; i < ctx.column_alias_list().column_alias().size(); i++) {
r.getSelectList()
.set(
i,
new AliasedColumn(
(UnnamedColumn) r.getSelectList().get(i),
ctx.column_alias_list().column_alias(i).getText()));
}
}
return r;
}
}
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