dawidwys commented on code in PR #23612:
URL: https://github.com/apache/flink/pull/23612#discussion_r1444489301
##########
flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/operations/ShowDatabasesOperation.java:
##########
@@ -20,26 +20,108 @@
import org.apache.flink.annotation.Internal;
import org.apache.flink.table.api.internal.TableResultInternal;
+import org.apache.flink.table.functions.SqlLikeUtils;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static java.util.Objects.requireNonNull;
import static
org.apache.flink.table.api.internal.TableResultUtils.buildStringArrayResult;
/** Operation to describe a SHOW DATABASES statement. */
@Internal
public class ShowDatabasesOperation implements ShowOperation {
+ private final String preposition;
+ private final String catalogName;
+ private final LikeType likeType;
+ private final String likePattern;
+ private final boolean notLike;
+
+ public ShowDatabasesOperation() {
+ // "SHOW DATABASES" command with all options being default
+ this.preposition = null;
+ this.catalogName = null;
+ this.likeType = null;
+ this.likePattern = null;
+ this.notLike = false;
+ }
+
+ public ShowDatabasesOperation(String likeType, String likePattern, boolean
notLike) {
+ this.preposition = null;
+ this.catalogName = null;
+ if (likeType != null) {
+ this.likeType = LikeType.of(likeType);
+ this.likePattern = requireNonNull(likePattern, "Like pattern must
not be null");
+ this.notLike = notLike;
+ } else {
+ this.likeType = null;
+ this.likePattern = null;
+ this.notLike = false;
+ }
+ }
+
+ public ShowDatabasesOperation(
+ String preposition,
+ String catalogName,
+ String likeType,
+ String likePattern,
+ boolean notLike) {
+ this.preposition = preposition;
+ this.catalogName = catalogName;
+ if (likeType != null) {
+ this.likeType = LikeType.of(likeType);
+ this.likePattern = requireNonNull(likePattern, "Like pattern must
not be null");
+ this.notLike = notLike;
+ } else {
+ this.likeType = null;
+ this.likePattern = null;
+ this.notLike = false;
+ }
+ }
+
@Override
public String asSummaryString() {
- return "SHOW DATABASES";
+ StringBuilder builder = new StringBuilder();
+ builder.append("SHOW DATABASES");
+ if (preposition != null) {
+ builder.append(String.format(" %s %s", preposition, catalogName));
+ }
+ if (likeType != null) {
+ if (notLike) {
+ builder.append(String.format(" NOT %s '%s'", likeType.name(),
likePattern));
+ } else {
+ builder.append(String.format(" %s '%s'", likeType.name(),
likePattern));
+ }
+ }
+ return builder.toString();
}
@Override
public TableResultInternal execute(Context ctx) {
- String[] databases =
- ctx.getCatalogManager()
-
.getCatalogOrThrowException(ctx.getCatalogManager().getCurrentCatalog())
- .listDatabases().stream()
- .sorted()
- .toArray(String[]::new);
- return buildStringArrayResult("database name", databases);
+ String cName =
+ catalogName == null ?
ctx.getCatalogManager().getCurrentCatalog() : catalogName;
+ List<String> databases =
+
ctx.getCatalogManager().getCatalogOrThrowException(cName).listDatabases();
+
+ if (likeType != null) {
+ databases =
+ databases.stream()
+ .filter(
+ row -> {
+ if (likeType == LikeType.ILIKE) {
+ return notLike
+ != SqlLikeUtils.ilike(row,
likePattern, "\\");
+ } else if (likeType == LikeType.LIKE) {
+ return notLike
+ != SqlLikeUtils.like(row,
likePattern, "\\");
+ }
+ return false;
+ })
+ .collect(Collectors.toList());
+ }
+
+ return buildStringArrayResult(
+ "database name",
databases.stream().sorted().toArray(String[]::new));
Review Comment:
If `databases` is a `Stream<String>` you wouldn't need to collect the
filtering results.
```
Stream<String> databases =
ctx.getCatalogManager().getCatalogOrThrowException(cName).listDatabases().stream();
if (likeType != null) {
databases =
databases
.filter(
row -> {
if (likeType == LikeType.ILIKE) {
return notLike
!=
SqlLikeUtils.ilike(row, likePattern, "\\");
} else if (likeType ==
LikeType.LIKE) {
return notLike
!=
SqlLikeUtils.like(row, likePattern, "\\");
}
return false;
});
}
```
##########
flink-table/flink-table-api-java/src/main/java/org/apache/flink/table/operations/ShowDatabasesOperation.java:
##########
@@ -20,26 +20,108 @@
import org.apache.flink.annotation.Internal;
import org.apache.flink.table.api.internal.TableResultInternal;
+import org.apache.flink.table.functions.SqlLikeUtils;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import static java.util.Objects.requireNonNull;
import static
org.apache.flink.table.api.internal.TableResultUtils.buildStringArrayResult;
/** Operation to describe a SHOW DATABASES statement. */
@Internal
public class ShowDatabasesOperation implements ShowOperation {
+ private final String preposition;
Review Comment:
Is there a difference whether it is `FROM` or `IN` ? If there is no
difference, could we parse both, but use one of the two when unparsing? We
wouldn't need to store the original preposition.
##########
flink-table/flink-table-planner/src/main/java/org/apache/flink/table/planner/operations/converters/SqlShowDatabasesConverter.java:
##########
@@ -0,0 +1,51 @@
+/*
+ * 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.flink.table.planner.operations.converters;
+
+import org.apache.flink.sql.parser.dql.SqlShowDatabases;
+import org.apache.flink.table.catalog.CatalogManager;
+import org.apache.flink.table.operations.Operation;
+import org.apache.flink.table.operations.ShowDatabasesOperation;
+
+/** A converter for {@link SqlShowDatabases}. */
+public class SqlShowDatabasesConverter implements
SqlNodeConverter<SqlShowDatabases> {
+
+ @Override
+ public Operation convertSqlNode(SqlShowDatabases sqlShowDatabases,
ConvertContext context) {
+ if (sqlShowDatabases.getPreposition() == null) {
+ return new ShowDatabasesOperation(
+ sqlShowDatabases.getLikeType(),
+ sqlShowDatabases.getLikeSqlPattern(),
+ sqlShowDatabases.isNotLike());
+ } else {
+ CatalogManager catalogManager = context.getCatalogManager();
+ String[] fullCatalogName = sqlShowDatabases.getCatalog();
+ String catalogName =
+ fullCatalogName.length == 0
+ ? catalogManager.getCurrentCatalog()
+ : fullCatalogName[0];
Review Comment:
Do we need to get the current catalog at this point? You handle that during
the execution already, don't you?
##########
docs/content.zh/docs/dev/table/sql/show.md:
##########
@@ -507,10 +507,21 @@ SHOW CURRENT CATALOG
## SHOW DATABASES
```sql
-SHOW DATABASES
+SHOW DATABASES [ ( FROM | IN ) catalog_name] [ [NOT] (LIKE | ILIKE)
<sql_like_pattern> ]
Review Comment:
Out of curiosity. Do you know chinese?
##########
flink-table/flink-sql-parser/src/main/java/org/apache/flink/sql/parser/dql/SqlShowDatabases.java:
##########
@@ -46,11 +100,40 @@ public SqlOperator getOperator() {
@Override
public List<SqlNode> getOperandList() {
- return Collections.EMPTY_LIST;
+ return catalogName == null
+ ? Collections.emptyList()
+ : Collections.singletonList(catalogName);
}
@Override
public void unparse(SqlWriter writer, int leftPrec, int rightPrec) {
- writer.keyword("SHOW DATABASES");
+ String resKeyword = "SHOW DATABASES";
+ writer.keyword(resKeyword);
Review Comment:
nit: inline `resKeyword`?
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