mirror of
https://github.com/RGBCube/serenity
synced 2025-07-25 03:57:43 +00:00
LibSQL: Implement a DESCRIBE TABLE statement
This statement (for now) outputs the name and types of the different attributes in a table. It's not standard SQL but all DBMSs that I know of implement a sort of statement for such functionality. Since the output of DESCRIBE TABLE is just a relation, an internal schema, `master` was created and a table definition for DESCRIBE into it. The table definition and the master schema are not accessible by the user.
This commit is contained in:
parent
cd4dba87fa
commit
f6233913ad
9 changed files with 93 additions and 0 deletions
42
Userland/Libraries/LibSQL/AST/Describe.cpp
Normal file
42
Userland/Libraries/LibSQL/AST/Describe.cpp
Normal file
|
@ -0,0 +1,42 @@
|
|||
/*
|
||||
* Copyright (c) 2021, Mahmoud Mandour <ma.mandourr@gmail.com>
|
||||
*
|
||||
* SPDX-License-Identifier: BSD-2-Clause
|
||||
*/
|
||||
|
||||
#include <LibSQL/AST/AST.h>
|
||||
#include <LibSQL/Database.h>
|
||||
#include <LibSQL/Meta.h>
|
||||
#include <LibSQL/Row.h>
|
||||
|
||||
namespace SQL::AST {
|
||||
|
||||
RefPtr<SQLResult> DescribeTable::execute(ExecutionContext& context) const
|
||||
{
|
||||
auto schema_name = m_qualified_table_name->schema_name();
|
||||
auto table_name = m_qualified_table_name->table_name();
|
||||
|
||||
auto table_def_or_error = context.database->get_table(schema_name, table_name);
|
||||
auto table_def = table_def_or_error.release_value();
|
||||
if (!table_def) {
|
||||
if (schema_name.is_null() || schema_name.is_empty())
|
||||
schema_name = "default";
|
||||
return SQLResult::construct(SQLCommand::Describe, SQLErrorCode::TableDoesNotExist, String::formatted("{}.{}", schema_name, table_name));
|
||||
}
|
||||
|
||||
auto describe_table_def = context.database->get_table("master", "internal_describe_table").value();
|
||||
NonnullRefPtr<TupleDescriptor> descriptor = describe_table_def->to_tuple_descriptor();
|
||||
|
||||
context.result = SQLResult::construct();
|
||||
|
||||
for (auto& column : table_def->columns()) {
|
||||
Tuple tuple(descriptor);
|
||||
tuple[0] = column.name();
|
||||
tuple[1] = SQLType_name(column.type());
|
||||
context.result->insert(tuple, Tuple {});
|
||||
}
|
||||
|
||||
return context.result;
|
||||
}
|
||||
|
||||
}
|
Loading…
Add table
Add a link
Reference in a new issue