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org.h2.expression.ExpressionColumn Maven / Gradle / Ivy
/*
* Copyright 2004-2019 H2 Group. Multiple-Licensed under the MPL 2.0,
* and the EPL 1.0 (https://h2database.com/html/license.html).
* Initial Developer: H2 Group
*/
package org.h2.expression;
import org.h2.api.ErrorCode;
import org.h2.command.Parser;
import org.h2.command.dml.Select;
import org.h2.command.dml.SelectGroups;
import org.h2.command.dml.SelectListColumnResolver;
import org.h2.engine.Database;
import org.h2.engine.Session;
import org.h2.expression.condition.Comparison;
import org.h2.index.IndexCondition;
import org.h2.message.DbException;
import org.h2.schema.Constant;
import org.h2.schema.Schema;
import org.h2.table.Column;
import org.h2.table.ColumnResolver;
import org.h2.table.Table;
import org.h2.table.TableFilter;
import org.h2.value.ExtTypeInfo;
import org.h2.value.TypeInfo;
import org.h2.value.Value;
import org.h2.value.ValueBoolean;
import org.h2.value.ValueNull;
/**
* A expression that represents a column of a table or view.
*/
public class ExpressionColumn extends Expression {
private final Database database;
private final String schemaName;
private final String tableAlias;
private String columnName;
private final boolean rowId;
private ColumnResolver columnResolver;
private int queryLevel;
private Column column;
public ExpressionColumn(Database database, Column column) {
this.database = database;
this.column = column;
this.schemaName = null;
this.tableAlias = null;
this.columnName = null;
this.rowId = column.isRowId();
}
public ExpressionColumn(Database database, String schemaName,
String tableAlias, String columnName, boolean rowId) {
this.database = database;
this.schemaName = schemaName;
this.tableAlias = tableAlias;
this.columnName = columnName;
this.rowId = rowId;
}
@Override
public StringBuilder getSQL(StringBuilder builder, boolean alwaysQuote) {
if (schemaName != null) {
Parser.quoteIdentifier(builder, schemaName, alwaysQuote).append('.');
}
if (tableAlias != null) {
Parser.quoteIdentifier(builder, tableAlias, alwaysQuote).append('.');
}
if (column != null) {
if (columnResolver != null && columnResolver.hasDerivedColumnList()) {
Parser.quoteIdentifier(builder, columnResolver.getColumnName(column), alwaysQuote);
} else {
column.getSQL(builder, alwaysQuote);
}
} else if (rowId) {
builder.append(columnName);
} else {
Parser.quoteIdentifier(builder, columnName, alwaysQuote);
}
return builder;
}
public TableFilter getTableFilter() {
return columnResolver == null ? null : columnResolver.getTableFilter();
}
@Override
public void mapColumns(ColumnResolver resolver, int level, int state) {
if (tableAlias != null && !database.equalsIdentifiers(
tableAlias, resolver.getTableAlias())) {
return;
}
if (schemaName != null && !database.equalsIdentifiers(
schemaName, resolver.getSchemaName())) {
return;
}
if (rowId) {
Column col = resolver.getRowIdColumn();
if (col != null) {
mapColumn(resolver, col, level);
}
return;
}
Column col = resolver.findColumn(columnName);
if (col != null) {
mapColumn(resolver, col, level);
return;
}
Column[] columns = resolver.getSystemColumns();
for (int i = 0; columns != null && i < columns.length; i++) {
col = columns[i];
if (database.equalsIdentifiers(columnName, col.getName())) {
mapColumn(resolver, col, level);
return;
}
}
}
private void mapColumn(ColumnResolver resolver, Column col, int level) {
if (this.columnResolver == null) {
queryLevel = level;
column = col;
this.columnResolver = resolver;
} else if (queryLevel == level && this.columnResolver != resolver) {
if (resolver instanceof SelectListColumnResolver) {
// ignore - already mapped, that's ok
} else {
throw DbException.get(ErrorCode.AMBIGUOUS_COLUMN_NAME_1, columnName);
}
}
}
@Override
public Expression optimize(Session session) {
if (columnResolver == null) {
Schema schema = session.getDatabase().findSchema(
tableAlias == null ? session.getCurrentSchemaName() : tableAlias);
if (schema != null) {
Constant constant = schema.findConstant(columnName);
if (constant != null) {
return constant.getValue();
}
}
throw getColumnException(ErrorCode.COLUMN_NOT_FOUND_1);
}
return columnResolver.optimize(this, column);
}
/**
* Get exception to throw, with column and table info added
* @param code SQL error code
* @return DbException
*/
public DbException getColumnException(int code) {
String name = columnName;
if (tableAlias != null) {
name = tableAlias + '.' + name;
if (schemaName != null) {
name = schemaName + '.' + name;
}
}
return DbException.get(code, name);
}
@Override
public void updateAggregate(Session session, int stage) {
Select select = columnResolver.getSelect();
if (select == null) {
throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL(false));
}
SelectGroups groupData = select.getGroupDataIfCurrent(false);
if (groupData == null) {
// this is a different level (the enclosing query)
return;
}
Value v = (Value) groupData.getCurrentGroupExprData(this);
if (v == null) {
groupData.setCurrentGroupExprData(this, columnResolver.getValue(column));
} else if (!select.isGroupWindowStage2()) {
if (!database.areEqual(columnResolver.getValue(column), v)) {
throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL(false));
}
}
}
@Override
public Value getValue(Session session) {
Select select = columnResolver.getSelect();
if (select != null) {
SelectGroups groupData = select.getGroupDataIfCurrent(false);
if (groupData != null) {
Value v = (Value) groupData.getCurrentGroupExprData(this);
if (v != null) {
return v;
}
if (select.isGroupWindowStage2()) {
throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL(false));
}
}
}
Value value = columnResolver.getValue(column);
if (value == null) {
if (select == null) {
throw DbException.get(ErrorCode.NULL_NOT_ALLOWED, getSQL(false));
} else {
throw DbException.get(ErrorCode.MUST_GROUP_BY_COLUMN_1, getSQL(false));
}
}
/*
* ENUM values are stored as integers.
*/
if (value != ValueNull.INSTANCE) {
ExtTypeInfo extTypeInfo = column.getType().getExtTypeInfo();
if (extTypeInfo != null) {
return extTypeInfo.cast(value);
}
}
return value;
}
@Override
public TypeInfo getType() {
return column == null ? TypeInfo.TYPE_UNKNOWN : column.getType();
}
@Override
public void setEvaluatable(TableFilter tableFilter, boolean b) {
}
public Column getColumn() {
return column;
}
public String getOriginalColumnName() {
return columnName;
}
public String getOriginalTableAliasName() {
return tableAlias;
}
@Override
public String getColumnName() {
if (column != null) {
if (columnResolver != null) {
return columnResolver.getColumnName(column);
}
return column.getName();
}
return columnName;
}
@Override
public String getSchemaName() {
Table table = column.getTable();
return table == null ? null : table.getSchema().getName();
}
@Override
public String getTableName() {
Table table = column.getTable();
return table == null ? null : table.getName();
}
@Override
public String getAlias() {
if (column != null) {
if (columnResolver != null) {
return columnResolver.getColumnName(column);
}
return column.getName();
}
if (tableAlias != null) {
return tableAlias + '.' + columnName;
}
return columnName;
}
@Override
public boolean isAutoIncrement() {
return column.getSequence() != null;
}
@Override
public int getNullable() {
return column.isNullable() ? Column.NULLABLE : Column.NOT_NULLABLE;
}
@Override
public boolean isEverything(ExpressionVisitor visitor) {
switch (visitor.getType()) {
case ExpressionVisitor.OPTIMIZABLE_AGGREGATE:
return false;
case ExpressionVisitor.READONLY:
case ExpressionVisitor.DETERMINISTIC:
case ExpressionVisitor.QUERY_COMPARABLE:
return true;
case ExpressionVisitor.INDEPENDENT:
return this.queryLevel < visitor.getQueryLevel();
case ExpressionVisitor.EVALUATABLE:
// if this column belongs to a 'higher level' query and is
// therefore just a parameter
if (visitor.getQueryLevel() < this.queryLevel) {
return true;
}
if (getTableFilter() == null) {
return false;
}
return getTableFilter().isEvaluatable();
case ExpressionVisitor.SET_MAX_DATA_MODIFICATION_ID:
visitor.addDataModificationId(column.getTable().getMaxDataModificationId());
return true;
case ExpressionVisitor.NOT_FROM_RESOLVER:
return columnResolver != visitor.getResolver();
case ExpressionVisitor.GET_DEPENDENCIES:
if (column != null) {
visitor.addDependency(column.getTable());
}
return true;
case ExpressionVisitor.GET_COLUMNS1:
if (column == null) {
throw DbException.get(ErrorCode.COLUMN_NOT_FOUND_1, getSQL(false));
}
visitor.addColumn1(column);
return true;
case ExpressionVisitor.GET_COLUMNS2:
if (column == null) {
throw DbException.get(ErrorCode.COLUMN_NOT_FOUND_1, getSQL(false));
}
visitor.addColumn2(column);
return true;
default:
throw DbException.throwInternalError("type=" + visitor.getType());
}
}
@Override
public int getCost() {
return 2;
}
@Override
public void createIndexConditions(Session session, TableFilter filter) {
TableFilter tf = getTableFilter();
if (filter == tf && column.getType().getValueType() == Value.BOOLEAN) {
IndexCondition cond = IndexCondition.get(
Comparison.EQUAL, this, ValueExpression.get(
ValueBoolean.TRUE));
filter.addIndexCondition(cond);
}
}
@Override
public Expression getNotIfPossible(Session session) {
return new Comparison(session, Comparison.EQUAL, this, ValueExpression.getBoolean(false));
}
}
