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feat: add DataType::Char and add LEN to Describe#174

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KKould merged 8 commits intoKipData:mainfrom
KKould:feat/char_type
Mar 21, 2024
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feat: add DataType::Char and add LEN to Describe#174
KKould merged 8 commits intoKipData:mainfrom
KKould:feat/char_type

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@KKould KKould commented Mar 21, 2024 •
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What problem does this PR solve?

let _ = fnck_sql
    .run("CREATE TABLE TABLE_E021_02_01_05 ( ID INT PRIMARY KEY, A CHAR ( 8 ) )")
    .await?;
let (schema, tuples) = fnck_sql.run("describe TABLE_E021_02_01_05").await?;
println!("{}", create_table(&schema, &tuples));
+-------+---------+-----+-------+---------+---------+
| FIELD | TYPE    | LEN | NULL  | Key     | DEFAULT |
+===================================================+
| id    | INTEGER | 4   | false | PRIMARY | null    |
|-------+---------+-----+-------+---------+---------|
| a     | CHAR    | 8   | true  | EMPTY   | null    |
+-------+---------+-----+-------+---------+---------+

on mysql

mysql> insert into T1 (A) VALUES('      abc   ');
Query OK, 1 row affected (0.00 sec)

mysql> select * from T1;
+-----------+
| A         |
+-----------+
| abc       |
|       abc |
+-----------+
2 rows in set (0.00 sec)

Issue link: #130

Code changes

  • Has Rust code change
  • Has CI related scripts change

Check List

Tests

  • Unit test
  • Integration test
  • Manual test (add detailed scripts or steps below)
  • No code

Side effects

  • Performance regression: Consumes more CPU
  • Performance regression: Consumes more Memory
  • Breaking backward compatibility

Note for reviewer

@KKould KKould requested a review from crwen March 21, 2024 11:49
@KKould KKould self-assigned this Mar 21, 2024
@KKould KKould added the documentation Improvements or additions to documentation label Mar 21, 2024
@KKould KKould mentioned this pull request Mar 21, 2024
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@KKould KKould added enhancement New feature or request and removed documentation Improvements or additions to documentation labels Mar 21, 2024
crwen
crwen reviewed Mar 21, 2024
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@crwen crwen left a comment •
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select * from t;
ERROR:  Unsupported Datatype CHAR

You need add LogicalType::Char to into_pg_type method

crwen
crwen reviewed Mar 21, 2024
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crwen
crwen reviewed Mar 21, 2024
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src/types/value.rs
Comment on lines +453 to +460
// https://dev.mysql.com/doc/refman/8.0/en/char.html#:~:text=If%20a%20given%20value%20is%20stored%20into%20the%20CHAR(4)%20and%20VARCHAR(4)%20columns%2C%20the%20values%20retrieved%20from%20the%20columns%20are%20not%20always%20the%20same%20because%20trailing%20spaces%20are%20removed%20from%20CHAR%20columns%20upon%20retrieval.%20The%20following%20example%20illustrates%20this%20difference%3A
let value = (!bytes.is_empty()).then(|| {
let last_non_zero_index = match bytes.iter().rposition(|&x| x != b' ') {
Some(index) => index + 1,
None => 0,
};
String::from_utf8(bytes[0..last_non_zero_index].to_owned()).unwrap()
});
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@crwen crwen Mar 21, 2024

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maybe use trim_end()

String::from_utf8(bytes.to_owned()).unwrap().trim_end();

and the link is too long 😂

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@KKould KKould Mar 21, 2024 •
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I tried it and it will make ' foo ' become 'foo', but it should be ' foo' in mysql

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@crwen crwen Mar 21, 2024

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trim_end only remove trailing whitespace. You might used trim().

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@KKould KKould Mar 21, 2024

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trim_end only remove trailing whitespace. You might used trim().

oh, you are right, but I found that trim_end() returns &str, which may cause String to be copied again.

@KKould KKould requested a review from crwen March 21, 2024 16:19
@KKould KKould merged commit 253daa8 into KipData:main Mar 21, 2024
@KKould KKould mentioned this pull request Mar 26, 2024
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@KKould KKould added this to the SQL 2016 milestone Jul 26, 2025
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