Java 类com.facebook.presto.sql.tree.ShowSchemas 实例源码

@Override
protected Void visitShowSchemas(ShowSchemas node, Integer context)
{
    builder.append("SHOW SCHEMAS");

    if (node.getCatalog().isPresent()) {
        builder.append(" FROM ")
                .append(node.getCatalog().get());
    }

    node.getLikePattern().ifPresent((value) ->
            builder.append(" LIKE ")
                    .append(formatStringLiteral(value)));

    return null;
}

@Override
protected RelationType visitShowSchemas(ShowSchemas node, AnalysisContext context)
{
    if (!node.getCatalog().isPresent() && !session.getCatalog().isPresent()) {
        throw new SemanticException(CATALOG_NOT_SPECIFIED, node, "Catalog must be specified when session catalog is not set");
    }

    Query query = simpleQuery(
            selectList(aliasedName("schema_name", "Schema")),
            from(node.getCatalog().orElseGet(() -> session.getCatalog().get()), TABLE_SCHEMATA),
            ordering(ascending("schema_name")));

    return process(query, context);
}

@Override
protected Void visitShowSchemas(ShowSchemas node, Integer context)
{
    builder.append("SHOW SCHEMAS");

    if (node.getCatalog().isPresent()) {
        builder.append(" FROM ")
                .append(node.getCatalog().get());
    }

    return null;
}

@Test
public void testShowSchemas()
        throws Exception
{
    assertStatement("SHOW SCHEMAS", new ShowSchemas(Optional.<String>empty()));
    assertStatement("SHOW SCHEMAS FROM foo", new ShowSchemas(Optional.of("foo")));
    assertStatement("SHOW SCHEMAS IN foo", new ShowSchemas(Optional.of("foo")));
}

@Override
protected Void visitShowSchemas(ShowSchemas node, Integer context)
{
    builder.append("SHOW SCHEMAS");

    if (node.getCatalog().isPresent()) {
        builder.append(" FROM ")
                .append(node.getCatalog().get());
    }

    return null;
}

@Override
public Node visitShowSchemas(SqlBaseParser.ShowSchemasContext context)
{
    return new ShowSchemas(getLocation(context), getTextIfPresent(context.identifier()));
}