org.apache.calcite.sql.ddl.SqlCheckConstraint Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you 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.apache.calcite.sql.ddl;
import org.apache.calcite.sql.SqlCall;
import org.apache.calcite.sql.SqlIdentifier;
import org.apache.calcite.sql.SqlKind;
import org.apache.calcite.sql.SqlNode;
import org.apache.calcite.sql.SqlOperator;
import org.apache.calcite.sql.SqlSpecialOperator;
import org.apache.calcite.sql.SqlWriter;
import org.apache.calcite.sql.parser.SqlParserPos;
import org.apache.calcite.util.ImmutableNullableList;
import java.util.List;
/**
* Parse tree for {@code UNIQUE}, {@code PRIMARY KEY} constraints.
*
* And {@code FOREIGN KEY}, when we support it.
*/
public class SqlCheckConstraint extends SqlCall {
private static final SqlSpecialOperator OPERATOR =
new SqlSpecialOperator("CHECK", SqlKind.CHECK);
private final SqlIdentifier name;
private final SqlNode expression;
/** Creates a SqlCheckConstraint; use {@link SqlDdlNodes#check}. */
SqlCheckConstraint(SqlParserPos pos, SqlIdentifier name,
SqlNode expression) {
super(pos);
this.name = name; // may be null
this.expression = expression;
}
@Override public SqlOperator getOperator() {
return OPERATOR;
}
@Override public List getOperandList() {
return ImmutableNullableList.of(name, expression);
}
@Override public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
if (name != null) {
writer.keyword("CONSTRAINT");
name.unparse(writer, 0, 0);
}
writer.keyword("CHECK");
if (writer.isAlwaysUseParentheses()) {
expression.unparse(writer, 0, 0);
} else {
writer.sep("(");
expression.unparse(writer, 0, 0);
writer.sep(")");
}
}
}
// End SqlCheckConstraint.java