196 lines
3.9 KiB
Java
196 lines
3.9 KiB
Java
/*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Other licenses:
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* -----------------------------------------------------------------------------
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* Commercial licenses for this work are available. These replace the above
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* ASL 2.0 and offer limited warranties, support, maintenance, and commercial
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* database integrations.
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*
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* For more information, please visit: http://www.jooq.org/licenses
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*
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*/
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package org.jooq.impl;
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import static org.jooq.impl.DSL.inline;
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import static org.jooq.impl.DSL.select;
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import org.jooq.Context;
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import org.jooq.Field;
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import org.jooq.Name;
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import org.jooq.Record;
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import org.jooq.Schema;
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import org.jooq.Table;
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/**
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* @author Lukas Eder
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*/
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final class Dual extends AbstractTable<Record> {
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private static final long serialVersionUID = -7492790780048090156L;
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private static final Table<Record> FORCED_DUAL = select(new Field[] { inline("X").as("DUMMY") }).asTable("DUAL");
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static final String DUAL_HSQLDB = "select 1 as dual from information_schema.system_users limit 1";
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static final Name DUAL_FIREBIRD = DSL.unquotedName("RDB$DATABASE");
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static final Name DUAL_CUBRID = DSL.unquotedName("db_root");
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static final Name DUAL_DERBY = DSL.unquotedName("SYSIBM", "SYSDUMMY1");
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private final boolean force;
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Dual() {
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this(false);
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}
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Dual(boolean force) {
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super(DSL.name("dual"), (Schema) null);
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this.force = force;
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}
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@Override
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public final Class<? extends Record> getRecordType() {
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return RecordImpl.class;
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}
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@Override
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public final Table<Record> as(Name alias) {
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if (force) {
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return FORCED_DUAL.as(alias);
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}
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else {
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return new TableAlias<Record>(this, alias);
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}
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}
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@Override
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public final Table<Record> as(Name alias, Name... fieldAliases) {
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if (force) {
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return FORCED_DUAL.as(alias, fieldAliases);
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}
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else {
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return new TableAlias<Record>(this, alias, fieldAliases);
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}
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}
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@Override
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public boolean declaresTables() {
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return true;
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}
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@Override
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public final void accept(Context<?> ctx) {
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if (force) {
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ctx.visit(FORCED_DUAL);
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}
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else {
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switch (ctx.family()) {
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case H2:
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case POSTGRES:
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case SQLITE:
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break;
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case FIREBIRD:
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ctx.visit(DUAL_FIREBIRD);
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break;
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case HSQLDB:
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ctx.sql('(').sql(DUAL_HSQLDB).sql(") as dual");
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break;
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case CUBRID:
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ctx.visit(DUAL_CUBRID);
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break;
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// These dialects don't have a DUAL table. But emulation is needed
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// for queries like SELECT 1 WHERE 1 = 1
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case DERBY:
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ctx.visit(DUAL_DERBY);
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break;
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case MARIADB:
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case MYSQL:
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default:
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ctx.sql("dual");
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break;
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}
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}
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}
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@Override
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final Fields<Record> fields0() {
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return new Fields<Record>();
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}
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}
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