package com.salesforce.phoenix.compile;
import java.sql.SQLException;
import java.util.Map;
import com.salesforce.phoenix.parse.ColumnParseNode;
import com.salesforce.phoenix.parse.FamilyWildcardParseNode;
import com.salesforce.phoenix.parse.ParseNode;
import com.salesforce.phoenix.parse.ParseNodeFactory;
import com.salesforce.phoenix.parse.ParseNodeRewriter;
import com.salesforce.phoenix.parse.SelectStatement;
import com.salesforce.phoenix.parse.TableName;
import com.salesforce.phoenix.parse.WildcardParseNode;
import com.salesforce.phoenix.schema.ColumnRef;
import com.salesforce.phoenix.schema.PDataType;
import com.salesforce.phoenix.schema.TableRef;
import com.salesforce.phoenix.util.IndexUtil;
public class IndexStatementRewriter extends ParseNodeRewriter {
private static final ParseNodeFactory FACTORY = new ParseNodeFactory();
private Map<TableRef, TableRef> multiTableRewriteMap;
public IndexStatementRewriter(ColumnResolver dataResolver, Map<TableRef, TableRef> multiTableRewriteMap) {
super(dataResolver);
this.multiTableRewriteMap = multiTableRewriteMap;
}
/**
* Rewrite the select statement by translating all data table column references to
* references to the corresponding index column.
* @param statement the select statement
* @param dataResolver the column resolver
* @return new select statement or the same one if nothing was rewritten.
* @throws SQLException
*/
public static SelectStatement translate(SelectStatement statement, ColumnResolver dataResolver) throws SQLException {
return translate(statement, dataResolver, null);
}
/**
* Rewrite the select statement containing multiple tables by translating all
* data table column references to references to the corresponding index column.
* @param statement the select statement
* @param dataResolver the column resolver
* @param multiTableRewriteMap the data table to index table map
* @return new select statement or the same one if nothing was rewritten.
* @throws SQLException
*/
public static SelectStatement translate(SelectStatement statement, ColumnResolver dataResolver, Map<TableRef, TableRef> multiTableRewriteMap) throws SQLException {
return rewrite(statement, new IndexStatementRewriter(dataResolver, multiTableRewriteMap));
}
@Override
public ParseNode visit(ColumnParseNode node) throws SQLException {
ColumnRef dataColRef = getResolver().resolveColumn(node.getSchemaName(), node.getTableName(), node.getName());
TableName tName = null;
if (multiTableRewriteMap != null) {
TableRef origRef = dataColRef.getTableRef();
TableRef tableRef = multiTableRewriteMap.get(origRef);
if (tableRef == null)
return node;
if (origRef.getTableAlias() != null) {
tName = FACTORY.table(null, origRef.getTableAlias());
} else {
String schemaName = tableRef.getTable().getSchemaName().getString();
schemaName = schemaName.length() == 0 ? null : '"' + schemaName + '"';
String tableName = '"' + tableRef.getTable().getTableName().getString() + '"';
tName = FACTORY.table(schemaName, tableName);
}
}
String indexColName = IndexUtil.getIndexColumnName(dataColRef.getColumn());
// Same alias as before, but use the index column name instead of the data column name
ParseNode indexColNode = new ColumnParseNode(tName, indexColName, node.getAlias());
PDataType indexColType = IndexUtil.getIndexColumnDataType(dataColRef.getColumn());
PDataType dataColType = dataColRef.getColumn().getDataType();
// Coerce index column reference back to same type as data column so that
// expression behave exactly the same. No need to invert, as this will be done
// automatically as needed. If node is used at the top level, do not convert, as
// otherwise the wrapper gets in the way in the group by clause. For example,
// an INTEGER column in a GROUP BY gets doubly wrapped like this:
// CAST CAST int_col AS INTEGER AS DECIMAL
// This is unnecessary and problematic in the case of a null value.
// TODO: test case for this
if (!isTopLevel() && indexColType != dataColType) {
indexColNode = FACTORY.cast(indexColNode, dataColType);
}
return indexColNode;
}
@Override
public ParseNode visit(WildcardParseNode node) throws SQLException {
return WildcardParseNode.REWRITE_INSTANCE;
}
@Override
public ParseNode visit(FamilyWildcardParseNode node) throws SQLException {
return new FamilyWildcardParseNode(node, true);
}
}