nu_command/stor/
delete.rs

1use crate::database::{MEMORY_DB, SQLiteDatabase, get_shared_mem_conn};
2use nu_engine::command_prelude::*;
3use nu_protocol::shell_error::generic::GenericError;
4use std::fmt::Write;
5
6#[derive(Clone)]
7pub struct StorDelete;
8
9impl Command for StorDelete {
10    fn name(&self) -> &str {
11        "stor delete"
12    }
13
14    fn signature(&self) -> Signature {
15        Signature::build("stor delete")
16            .input_output_types(vec![(Type::Nothing, Type::table())])
17            .required_named(
18                "table-name",
19                SyntaxShape::String,
20                "Name of the table you want to delete or delete from.",
21                Some('t'),
22            )
23            .named(
24                "where-clause",
25                SyntaxShape::String,
26                "A sql string to use as a where clause without the WHERE keyword.",
27                Some('w'),
28            )
29            .allow_variants_without_examples(true)
30            .category(Category::Database)
31    }
32
33    fn description(&self) -> &str {
34        "Delete a table or specified rows in the in-memory sqlite database."
35    }
36
37    fn search_terms(&self) -> Vec<&str> {
38        vec!["sqlite", "remove", "table", "saving", "drop"]
39    }
40
41    fn examples(&self) -> Vec<Example<'_>> {
42        vec![
43            Example {
44                description: "Delete a table from the in-memory sqlite database",
45                example: "stor delete --table-name nudb",
46                result: None,
47            },
48            Example {
49                description: "Delete some rows from the in-memory sqlite database with a where clause",
50                example: "stor delete --table-name nudb --where-clause \"int1 == 5\"",
51                result: None,
52            },
53        ]
54    }
55
56    fn run(
57        &self,
58        engine_state: &EngineState,
59        stack: &mut Stack,
60        call: &Call,
61        _input: PipelineData,
62    ) -> Result<PipelineData, ShellError> {
63        let span = call.head;
64        // For dropping/deleting an entire table
65        let table_name_opt: Option<String> = call.get_flag(engine_state, stack, "table-name")?;
66
67        // For deleting rows from a table
68        let where_clause_opt: Option<String> =
69            call.get_flag(engine_state, stack, "where-clause")?;
70
71        if table_name_opt.is_none() && where_clause_opt.is_none() {
72            return Err(ShellError::MissingParameter {
73                param_name: "requires at least one of table-name or where-clause".into(),
74                span,
75            });
76        }
77
78        if table_name_opt.is_none() && where_clause_opt.is_some() {
79            return Err(ShellError::MissingParameter {
80                param_name: "using the where-clause requires the use of a table-name".into(),
81                span,
82            });
83        }
84
85        if let Some(new_table_name) = table_name_opt {
86            let conn = get_shared_mem_conn()?;
87            let sql_stmt = match where_clause_opt {
88                None => {
89                    // We're deleting an entire table
90                    format!("DROP TABLE {new_table_name}")
91                }
92                Some(where_clause) => {
93                    // We're just deleting some rows
94                    let mut delete_stmt = format!("DELETE FROM {new_table_name} ");
95
96                    // Yup, this is a bit janky, but I'm not sure a better way to do this without having
97                    // --and and --or flags as well as supporting ==, !=, <>, is null, is not null, etc.
98                    // and other sql syntax. So, for now, just type a sql where clause as a string.
99                    write!(delete_stmt, "WHERE {where_clause}")
100                        .expect("writing to a String is infallible");
101                    delete_stmt
102                }
103            };
104
105            // dbg!(&sql_stmt);
106            conn.execute(&sql_stmt, []).map_err(|err| {
107                ShellError::Generic(GenericError::new_internal(
108                    "Failed to delete using the SQLite connection to the in-memory database from delete.rs.",
109                    err.to_string(),
110                ))
111            })?;
112        }
113
114        let db = Box::new(SQLiteDatabase::new(
115            std::path::Path::new(MEMORY_DB),
116            engine_state.signals().clone(),
117        ));
118        Ok(Value::custom(db, span).into_pipeline_data())
119    }
120}
121
122#[cfg(test)]
123mod test {
124    use super::*;
125
126    #[test]
127    fn test_examples() -> nu_test_support::Result {
128        nu_test_support::test().examples(StorDelete)
129    }
130}
nu_command/stor/delete.rs

nu_command/stor/
delete.rs
