Database commands (#5343)

* dabase access commands

* select expression

* select using expressions

* cargo fmt

crates/nu-command/src/database/commands/mod.rs

@@ -6,19 +6,23 @@ mod open;
 mod query;
 mod schema;
 mod select;
-mod utils;
+
+// Temporal module to create Query objects
+mod testing;
+use testing::TestingDb;
+
+use nu_protocol::engine::StateWorkingSet;
 
 use collect::CollectDb;
 use command::Database;
 use describe::DescribeDb;
 use from::FromDb;
-use nu_protocol::engine::StateWorkingSet;
 use open::OpenDb;
 use query::QueryDb;
 use schema::SchemaDb;
-use select::SelectDb;
+use select::ProjectionDb;
 
-pub fn add_database_decls(working_set: &mut StateWorkingSet) {
+pub fn add_commands_decls(working_set: &mut StateWorkingSet) {
     macro_rules! bind_command {
             ( $command:expr ) => {
                 working_set.add_decl(Box::new($command));
@@ -29,5 +33,15 @@ pub fn add_database_decls(working_set: &mut StateWorkingSet) {
         }
 
     // Series commands
-    bind_command!(CollectDb, Database, DescribeDb, FromDb, QueryDb, SelectDb, OpenDb, SchemaDb);
+    bind_command!(
+        CollectDb,
+        Database,
+        DescribeDb,
+        FromDb,
+        QueryDb,
+        ProjectionDb,
+        OpenDb,
+        SchemaDb,
+        TestingDb
+    );
 }

crates/nu-command/src/database/commands/schema.rs

@@ -1,5 +1,5 @@
 use super::super::SQLiteDatabase;
-use crate::database::values::db_row::DbRow;
+use crate::database::values::definitions::db_row::DbRow;
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},

crates/nu-command/src/database/commands/select.rs

@@ -1,16 +1,16 @@
-use super::{super::SQLiteDatabase, utils::extract_strings};
+use super::{super::values::dsl::SelectDb, super::SQLiteDatabase};
 use nu_engine::CallExt;
 use nu_protocol::{
     ast::Call,
     engine::{Command, EngineState, Stack},
     Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, SyntaxShape, Value,
 };
-use sqlparser::ast::{Expr, Ident, Query, Select, SelectItem, SetExpr};
+use sqlparser::ast::{Query, Select, SelectItem, SetExpr};
 
 #[derive(Clone)]
-pub struct SelectDb;
+pub struct ProjectionDb;
 
-impl Command for SelectDb {
+impl Command for ProjectionDb {
     fn name(&self) -> &str {
         "db select"
     }
@@ -21,7 +21,7 @@ impl Command for SelectDb {
 
     fn signature(&self) -> Signature {
         Signature::build(self.name())
-            .required(
+            .rest(
                 "select",
                 SyntaxShape::Any,
                 "Select expression(s) on the table",
@@ -42,7 +42,7 @@ impl Command for SelectDb {
             },
             Example {
                 description: "selects columns from a database",
-                example: "db open db.mysql | db select [a, b, c]",
+                example: "db open db.mysql | db select a b c",
                 result: None,
             },
         ]
@@ -55,20 +55,24 @@ impl Command for SelectDb {
         call: &Call,
         input: PipelineData,
     ) -> Result<PipelineData, ShellError> {
-        let value: Value = call.req(engine_state, stack, 0)?;
-        let expressions = extract_strings(value)?;
+        let vals: Vec<Value> = call.rest(engine_state, stack, 0)?;
+        let value = Value::List {
+            vals,
+            span: call.head,
+        };
+        let projection = SelectDb::extract_selects(value)?;
 
         let mut db = SQLiteDatabase::try_from_pipeline(input, call.head)?;
         db.query = match db.query {
-            None => Some(create_query(expressions)),
-            Some(query) => Some(modify_query(query, expressions)),
+            None => Some(create_query(projection)),
+            Some(query) => Some(modify_query(query, projection)),
         };
 
         Ok(db.into_value(call.head).into_pipeline_data())
     }
 }
 
-fn create_query(expressions: Vec<String>) -> Query {
+fn create_query(expressions: Vec<SelectItem>) -> Query {
     Query {
         with: None,
         body: SetExpr::Select(Box::new(create_select(expressions))),
@@ -80,7 +84,7 @@ fn create_query(expressions: Vec<String>) -> Query {
     }
 }
 
-fn modify_query(mut query: Query, expressions: Vec<String>) -> Query {
+fn modify_query(mut query: Query, expressions: Vec<SelectItem>) -> Query {
     query.body = match query.body {
         SetExpr::Select(select) => SetExpr::Select(Box::new(modify_select(select, expressions))),
         _ => SetExpr::Select(Box::new(create_select(expressions))),
@@ -89,18 +93,18 @@ fn modify_query(mut query: Query, expressions: Vec<String>) -> Query {
     query
 }
 
-fn modify_select(select: Box<Select>, expressions: Vec<String>) -> Select {
+fn modify_select(select: Box<Select>, projection: Vec<SelectItem>) -> Select {
     Select {
-        projection: create_projection(expressions),
+        projection,
         ..select.as_ref().clone()
     }
 }
 
-fn create_select(expressions: Vec<String>) -> Select {
+fn create_select(projection: Vec<SelectItem>) -> Select {
     Select {
         distinct: false,
         top: None,
-        projection: create_projection(expressions),
+        projection,
         into: None,
         from: Vec::new(),
         lateral_views: Vec::new(),
@@ -112,20 +116,3 @@ fn create_select(expressions: Vec<String>) -> Select {
         having: None,
     }
 }
-
-// This function needs more work
-// It needs to define alias and functions in the columns
-// I assume we will need to define expressions for the columns instead of strings
-fn create_projection(expressions: Vec<String>) -> Vec<SelectItem> {
-    expressions
-        .into_iter()
-        .map(|expression| {
-            let expr = Expr::Identifier(Ident {
-                value: expression,
-                quote_style: None,
-            });
-
-            SelectItem::UnnamedExpr(expr)
-        })
-        .collect()
-}

crates/nu-command/src/database/commands/testing.rs

@@ -0,0 +1,76 @@
+use nu_engine::CallExt;
+use nu_protocol::{
+    ast::Call,
+    engine::{Command, EngineState, Stack},
+    Category, Example, IntoPipelineData, PipelineData, ShellError, Signature, Spanned, SyntaxShape,
+    Value,
+};
+use sqlparser::dialect::GenericDialect;
+use sqlparser::parser::Parser;
+
+#[derive(Clone)]
+pub struct TestingDb;
+
+impl Command for TestingDb {
+    fn name(&self) -> &str {
+        "db testing"
+    }
+
+    fn signature(&self) -> Signature {
+        Signature::build(self.name())
+            .required(
+                "query",
+                SyntaxShape::String,
+                "SQL to execute to create the query object",
+            )
+            .category(Category::Custom("database".into()))
+    }
+
+    fn usage(&self) -> &str {
+        "Create query object"
+    }
+
+    fn examples(&self) -> Vec<Example> {
+        vec![Example {
+            description: "",
+            example: "",
+            result: None,
+        }]
+    }
+
+    fn search_terms(&self) -> Vec<&str> {
+        vec!["database", "SQLite"]
+    }
+
+    fn run(
+        &self,
+        engine_state: &EngineState,
+        stack: &mut Stack,
+        call: &Call,
+        _input: PipelineData,
+    ) -> Result<PipelineData, ShellError> {
+        let sql: Spanned<String> = call.req(engine_state, stack, 0)?;
+
+        let dialect = GenericDialect {}; // or AnsiDialect, or your own dialect ...
+
+        let ast = Parser::parse_sql(&dialect, sql.item.as_str()).map_err(|e| {
+            ShellError::GenericError(
+                "Error creating AST".into(),
+                e.to_string(),
+                Some(sql.span),
+                None,
+                Vec::new(),
+            )
+        })?;
+
+        let value = match ast.get(0) {
+            None => Value::nothing(call.head),
+            Some(statement) => Value::String {
+                val: format!("{:#?}", statement),
+                span: call.head,
+            },
+        };
+
+        Ok(value.into_pipeline_data())
+    }
+}

crates/nu-command/src/database/commands/utils.rs

@@ -1,15 +0,0 @@
-use nu_protocol::{FromValue, ShellError, Value};
-
-pub fn extract_strings(value: Value) -> Result<Vec<String>, ShellError> {
-    match (
-        <String as FromValue>::from_value(&value),
-        <Vec<String> as FromValue>::from_value(&value),
-    ) {
-        (Ok(col), Err(_)) => Ok(vec![col]),
-        (Err(_), Ok(cols)) => Ok(cols),
-        _ => Err(ShellError::IncompatibleParametersSingle(
-            "Expected a string or list of strings".into(),
-            value.span()?,
-        )),
-    }
-}