在空表中查找SQLite列名 [英] Find SQLite Column Names in Empty Table

问题描述

对于踢，我写一个模式文档工具，生成一个数据库中的表和关系的描述。我现在shimming它与SQLite工作。

For kicks I'm writing a "schema documentation" tool that generates a description of the tables and relationships in a database. I'm currently shimming it to work with SQLite.

我设法提取SQLite数据库中的所有表的名称通过查询 sqlite_master 表。对于每个表名，我然后触发一个简单的

I've managed to extract the names of all the tables in a SQLite database via a query on the sqlite_master table. For each table name, I then fire off a simple

select * from <table name>

查询，然后使用 sqlite3_column_count（）和 sqlite3_column_name（）用于收集列名称的API，我进一步馈送到 sqlite3_table_column_metadata（）很简单，对吗？

query, then use the sqlite3_column_count() and sqlite3_column_name() APIs to collect the column names, which I further feed to sqlite3_table_column_metadata() to get additional info. Simple enough, right?

问题是它只适用于非空的表。也就是说， sqlite_column _ *（） API仅在 sqlite_step（）返回

The problem is that it only works for tables that are not empty. That is, the sqlite_column_*() APIs are only valid if sqlite_step() has returned SQLITE_ROW, which is not the case for empty tables.

因此，问题是，如何发现空表的列名？SQLite_ROW

So the question is, how can I discover column names for empty tables? Or, more generally, is there a better way to get this type of schema info in SQLite?

我想有一个隐藏的 sqlite_xxx 表潜伏在某处包含此信息，但到目前为止还没有找到它。

I feel like there must be another hidden sqlite_xxx table lurking somewhere containing this info, but so far have not been able to find it.

推荐答案

sqlite> .header on
sqlite> .mode column
sqlite> create table ABC(A TEXT, B VARCHAR);
sqlite> pragma table_info(ABC);
cid         name        type        notnull     dflt_value  pk
----------  ----------  ----------  ----------  ----------  ----------
0           A           TEXT        0                       0
1           B           VARCHAR     0                       0

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