feat: editable query results + empty SELECT rendering

src-tauri/src/commands/mod.rs

@@ -6,6 +6,7 @@ pub mod helpers;
 pub mod jdbc;
 pub mod query;
 pub mod server;
+pub mod sql_analysis;
 pub mod store;
 pub mod transfer;
 

src-tauri/src/commands/sql_analysis.rs

@@ -0,0 +1,384 @@
+//! SQL editability analysis.
+//!
+//! Parses a SELECT statement with sqlparser and decides whether its result rows
+//! can be mapped back to a single base table (and therefore edited/deleted).
+//! A result is editable only when the query is a plain single-table SELECT
+//! (optionally with WHERE/ORDER BY/LIMIT) whose rows map 1:1 to the table.
+
+use serde::{Deserialize, Serialize};
+use sqlparser::ast::{
+    Expr, GroupByExpr, ObjectNamePart, Query, Select, SelectItem, SetExpr, Statement, TableFactor,
+};
+use sqlparser::dialect::{GenericDialect, MsSqlDialect, MySqlDialect, PostgreSqlDialect};
+use sqlparser::parser::Parser;
+
+/// Why a query result cannot be edited.
+#[derive(Debug, Clone, Copy, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "kebab-case")]
+pub enum NonEditableReason {
+    /// Statement is not a SELECT (INSERT/UPDATE/DELETE/DDL...).
+    NotSelect,
+    /// Query starts with WITH (CTE) — row identity cannot be trusted.
+    Cte,
+    /// UNION/INTERSECT/EXCEPT — rows come from multiple statements.
+    SetOperation,
+    /// GROUP BY / HAVING / DISTINCT / aggregate functions — rows are aggregated.
+    Aggregation,
+    /// More than one table source (JOIN or comma-separated).
+    MultipleSources,
+    /// No FROM clause at all.
+    NoTable,
+    /// The FROM source is a subquery/table function/parenthesized join.
+    ComplexSource,
+}
+
+/// Result of analyzing whether a query's rows are editable.
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct SqlEditability {
+    pub editable: bool,
+    /// Present only when editable — the single base table the query reads from.
+    pub table_name: Option<String>,
+    pub schema: Option<String>,
+    pub reason: Option<NonEditableReason>,
+}
+
+fn dialect_for(db_type: &str) -> Box<dyn sqlparser::dialect::Dialect> {
+    match db_type.to_ascii_lowercase().as_str() {
+        "postgres" | "postgresql" | "duckdb" | "cockroachdb" | "gbase8c" | "kingbasees" | "yashandb"
+        | "xugudb" | "timescaledb" | "redshift" | "yugabytedb" | "opengauss" | "highgo" | "uxdb"
+        | "gaussdb" => Box::new(PostgreSqlDialect {}),
+        "mysql" | "clickhouse" | "oceanbase" | "mariadb" | "gbase8a" => Box::new(MySqlDialect {}),
+        "sqlserver" | "mssql" => Box::new(MsSqlDialect {}),
+        _ => Box::new(GenericDialect {}),
+    }
+}
+
+/// Analyze a SQL statement and report whether its result rows are editable.
+///
+/// Safe by construction: only plain single-table SELECTs map result rows back
+/// to base rows. Aggregations, set operations, CTEs, and multi-source queries
+/// are reported as non-editable with a machine-readable reason.
+pub fn analyze_sql_editability(sql: &str, db_type: &str) -> SqlEditability {
+    let dialect = dialect_for(db_type);
+    let Ok(statements) = Parser::parse_sql(&*dialect, sql) else {
+        return SqlEditability {
+            editable: false,
+            table_name: None,
+            schema: None,
+            reason: Some(NonEditableReason::ComplexSource),
+        };
+    };
+
+    if statements.len() != 1 {
+        return SqlEditability {
+            editable: false,
+            table_name: None,
+            schema: None,
+            reason: Some(NonEditableReason::NotSelect),
+        };
+    }
+
+    let Some(query) = as_select_query(&statements[0]) else {
+        return SqlEditability {
+            editable: false,
+            table_name: None,
+            schema: None,
+            reason: Some(NonEditableReason::NotSelect),
+        };
+    };
+
+    // WITH (CTE) — the top-level FROM may reference a CTE instead of a table.
+    if query.with.is_some() {
+        return non_editable(NonEditableReason::Cte);
+    }
+
+    // UNION/INTERSECT/EXCEPT — rows come from multiple statements.
+    if !matches!(query.body.as_ref(), SetExpr::Select(_)) {
+        return non_editable(NonEditableReason::SetOperation);
+    }
+
+    let SetExpr::Select(select) = query.body.as_ref() else {
+        return non_editable(NonEditableReason::SetOperation);
+    };
+
+    if select_is_aggregated(select) {
+        return non_editable(NonEditableReason::Aggregation);
+    }
+
+    if select.from.is_empty() {
+        return non_editable(NonEditableReason::NoTable);
+    }
+
+    // Exactly one FROM source, and it must be a plain table (no subquery,
+    // no table function, no parenthesized join).
+    if select.from.len() > 1 {
+        return non_editable(NonEditableReason::MultipleSources);
+    }
+
+    let table_with_joins = &select.from[0];
+    if !table_with_joins.joins.is_empty() {
+        return non_editable(NonEditableReason::MultipleSources);
+    }
+
+    let TableFactor::Table { name, .. } = &table_with_joins.relation else {
+        return non_editable(NonEditableReason::ComplexSource);
+    };
+
+    // Extract schema (second-to-last part) and table (last part).
+    let parts: Vec<&String> = name
+        .0
+        .iter()
+        .filter_map(ObjectNamePart::as_ident)
+        .map(|ident| &ident.value)
+        .collect();
+
+    let Some(table_name) = parts.last().cloned().cloned() else {
+        return non_editable(NonEditableReason::NoTable);
+    };
+
+    let schema = if parts.len() >= 2 {
+        Some(parts[parts.len() - 2].clone())
+    } else {
+        None
+    };
+
+    SqlEditability {
+        editable: true,
+        table_name: Some(table_name),
+        schema,
+        reason: None,
+    }
+}
+
+fn non_editable(reason: NonEditableReason) -> SqlEditability {
+    SqlEditability {
+        editable: false,
+        table_name: None,
+        schema: None,
+        reason: Some(reason),
+    }
+}
+
+fn as_select_query(statement: &Statement) -> Option<&Query> {
+    match statement {
+        Statement::Query(query) => Some(query),
+        _ => None,
+    }
+}
+
+/// True when the SELECT is aggregated: GROUP BY/HAVING/DISTINCT or an
+/// aggregate function in the projection. Aggregated rows do not map 1:1 to
+/// base-table rows.
+fn select_is_aggregated(select: &Select) -> bool {
+    if select.distinct.is_some() {
+        return true;
+    }
+    if matches!(select.group_by, GroupByExpr::Expressions(ref exprs, _) if !exprs.is_empty()) {
+        return true;
+    }
+    if select.having.is_some() {
+        return true;
+    }
+    select.projection.iter().any(projection_has_aggregate)
+}
+
+fn projection_has_aggregate(item: &SelectItem) -> bool {
+    match item {
+        SelectItem::UnnamedExpr(expr) | SelectItem::ExprWithAlias { expr, .. } => {
+            expr_has_aggregate(expr)
+        }
+        _ => false,
+    }
+}
+
+fn expr_has_aggregate(expr: &Expr) -> bool {
+    match expr {
+        Expr::Function(function) => {
+            if is_aggregate_function(&function.name.to_string()) {
+                return true;
+            }
+            expr_function_has_aggregate_arg(&function.args)
+                || function.filter.as_deref().is_some_and(expr_has_aggregate)
+        }
+        Expr::BinaryOp { left, right, .. } => expr_has_aggregate(left) || expr_has_aggregate(right),
+        Expr::Nested(inner) | Expr::IsNull(inner) | Expr::IsNotNull(inner) => expr_has_aggregate(inner),
+        Expr::UnaryOp { expr: inner, .. } => expr_has_aggregate(inner),
+        Expr::Case { operand, conditions, else_result, .. } => {
+            operand.as_deref().is_some_and(expr_has_aggregate)
+                || conditions
+                    .iter()
+                    .any(|cond| expr_has_aggregate(&cond.condition) || expr_has_aggregate(&cond.result))
+                || else_result.as_deref().is_some_and(expr_has_aggregate)
+        }
+        Expr::Subquery(query) | Expr::Exists { subquery: query, .. } => {
+            let mut found = false;
+            if let SetExpr::Select(select) = query.body.as_ref() {
+                found = select.projection.iter().any(projection_has_aggregate);
+            }
+            found
+        }
+        _ => false,
+    }
+}
+
+fn expr_function_has_aggregate_arg(args: &sqlparser::ast::FunctionArguments) -> bool {
+    match args {
+        sqlparser::ast::FunctionArguments::List(list) => list
+            .args
+            .iter()
+            .any(|arg| match arg {
+                sqlparser::ast::FunctionArg::Unnamed(sqlparser::ast::FunctionArgExpr::Expr(e)) => {
+                    expr_has_aggregate(e)
+                }
+                sqlparser::ast::FunctionArg::Named { arg, .. }
+                | sqlparser::ast::FunctionArg::ExprNamed { arg, .. } => match arg {
+                    sqlparser::ast::FunctionArgExpr::Expr(e) => expr_has_aggregate(e),
+                    _ => false,
+                },
+                _ => false,
+            }),
+        sqlparser::ast::FunctionArguments::Subquery(query) => {
+            let mut found = false;
+            if let SetExpr::Select(select) = query.body.as_ref() {
+                found = select.projection.iter().any(projection_has_aggregate);
+            }
+            found
+        }
+        sqlparser::ast::FunctionArguments::None => false,
+    }
+}
+
+fn is_aggregate_function(name: &str) -> bool {
+    matches!(
+        name.to_ascii_uppercase().as_str(),
+        "COUNT" | "SUM" | "AVG" | "MIN" | "MAX" | "STDDEV" | "STDDEV_POP" | "STDDEV_SAMP" | "VARIANCE"
+            | "VAR_POP" | "VAR_SAMP" | "ARRAY_AGG" | "STRING_AGG" | "JSON_AGG" | "JSONB_AGG"
+            | "BOOL_AND" | "BOOL_OR" | "EVERY"
+    )
+}
+
+/// Tauri command: analyze whether a query's result rows are editable.
+///
+/// Returns the single base table (with optional schema) when the query is a
+/// plain single-table SELECT; otherwise a machine-readable non-editable reason
+/// the frontend can surface to the user.
+#[tauri::command]
+pub fn analyze_sql_editability_command(sql: String, database_type: Option<String>) -> SqlEditability {
+    analyze_sql_editability(&sql, database_type.as_deref().unwrap_or("generic"))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn editable(sql: &str) -> bool {
+        analyze_sql_editability(sql, "postgres").editable
+    }
+
+    fn reason(sql: &str) -> Option<NonEditableReason> {
+        analyze_sql_editability(sql, "postgres").reason
+    }
+
+    #[test]
+    fn plain_select_star_is_editable() {
+        let result = analyze_sql_editability("SELECT * FROM apps", "postgres");
+        assert!(result.editable);
+        assert_eq!(result.table_name.as_deref(), Some("apps"));
+        assert_eq!(result.schema, None);
+    }
+
+    #[test]
+    fn select_with_qualifier_returns_schema() {
+        let result = analyze_sql_editability("SELECT * FROM public.apps", "postgres");
+        assert!(result.editable);
+        assert_eq!(result.table_name.as_deref(), Some("apps"));
+        assert_eq!(result.schema.as_deref(), Some("public"));
+    }
+
+    #[test]
+    fn select_with_where_order_limit_is_editable() {
+        assert!(editable("SELECT id, name FROM customers WHERE id > 10 ORDER BY name LIMIT 100"));
+    }
+
+    #[test]
+    fn quoted_table_name_is_editable() {
+        let result = analyze_sql_editability("SELECT * FROM \"My Table\"", "postgres");
+        assert!(result.editable);
+        assert_eq!(result.table_name.as_deref(), Some("My Table"));
+    }
+
+    #[test]
+    fn join_is_not_editable() {
+        assert!(!editable("SELECT a.*, b.* FROM a JOIN b ON a.id = b.id"));
+        assert_eq!(reason("SELECT a.*, b.* FROM a JOIN b ON a.id = b.id"), Some(NonEditableReason::MultipleSources));
+    }
+
+    #[test]
+    fn comma_separated_sources_is_not_editable() {
+        assert_eq!(reason("SELECT * FROM a, b"), Some(NonEditableReason::MultipleSources));
+    }
+
+    #[test]
+    fn count_aggregation_is_not_editable() {
+        assert_eq!(reason("SELECT COUNT(*) FROM apps"), Some(NonEditableReason::Aggregation));
+    }
+
+    #[test]
+    fn group_by_is_not_editable() {
+        assert_eq!(reason("SELECT name, COUNT(*) FROM customers GROUP BY name"), Some(NonEditableReason::Aggregation));
+    }
+
+    #[test]
+    fn distinct_is_not_editable() {
+        assert_eq!(reason("SELECT DISTINCT name FROM customers"), Some(NonEditableReason::Aggregation));
+    }
+
+    #[test]
+    fn union_is_not_editable() {
+        assert_eq!(reason("SELECT * FROM a UNION SELECT * FROM b"), Some(NonEditableReason::SetOperation));
+    }
+
+    #[test]
+    fn cte_is_not_editable() {
+        assert_eq!(
+            reason("WITH t AS (SELECT * FROM apps) SELECT * FROM t"),
+            Some(NonEditableReason::Cte)
+        );
+    }
+
+    #[test]
+    fn subquery_source_is_not_editable() {
+        assert_eq!(
+            reason("SELECT * FROM (SELECT * FROM apps) t"),
+            Some(NonEditableReason::ComplexSource)
+        );
+    }
+
+    #[test]
+    fn non_select_statement_is_not_editable() {
+        assert_eq!(reason("UPDATE apps SET name = 'x'"), Some(NonEditableReason::NotSelect));
+        assert_eq!(reason("DELETE FROM apps"), Some(NonEditableReason::NotSelect));
+        assert_eq!(reason("INSERT INTO apps (name) VALUES ('x')"), Some(NonEditableReason::NotSelect));
+    }
+
+    #[test]
+    fn multiple_statements_is_not_editable() {
+        assert_eq!(
+            reason("SELECT * FROM apps; SELECT * FROM orders"),
+            Some(NonEditableReason::NotSelect)
+        );
+    }
+
+    #[test]
+    fn mysql_backtick_table_is_editable() {
+        let result = analyze_sql_editability("SELECT * FROM `customers`", "mysql");
+        assert!(result.editable);
+        assert_eq!(result.table_name.as_deref(), Some("customers"));
+    }
+
+    #[test]
+    fn no_from_is_not_editable() {
+        assert_eq!(reason("SELECT 1"), Some(NonEditableReason::NoTable));
+    }
+}