Drop schema support

Author: zachmu

core/rootvalue.go

@@ -17,6 +17,7 @@ package core
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"slices"
 	"sort"
 	"strconv"
@@ -87,6 +88,35 @@ func (root *RootValue) CreateDatabaseSchema(ctx context.Context, dbSchema schema
 	return root.withStorage(r), nil
 }
 
+// DropDatabaseSchema implements the interface doltdb.RootValue.
+func (root *RootValue) DropDatabaseSchema(ctx context.Context, dbSchema schema.DatabaseSchema) (doltdb.RootValue, error) {
+	schemas, err := root.st.GetSchemas(ctx)
+	if err != nil {
+		return nil, err
+	}
+
+	found := false
+	for i, s := range schemas {
+		if strings.EqualFold(s.Name, dbSchema.Name) {
+			found = true
+			// remove this element in the slice
+			schemas = append(schemas[:i], schemas[i+1:]...)
+			break
+		}
+	}
+
+	if !found {
+		return nil, fmt.Errorf("No schema with the name %s exists", dbSchema.Name)
+	}
+
+	r, err := root.st.SetSchemas(ctx, schemas)
+	if err != nil {
+		return nil, err
+	}
+
+	return root.withStorage(r), nil
+}
+
 // validateSchemaForCreate returns an error if a schema with the name given cannot be created
 func validateSchemaForCreate(existingSchemas []schema.DatabaseSchema, dbSchema schema.DatabaseSchema) error {
 	if dbSchema.Name == "" {
@@ -579,10 +609,10 @@ func (root *RootValue) PutTable(ctx context.Context, tName doltdb.TableName, tab
 
 // RemoveTables implements the interface doltdb.RootValue.
 func (root *RootValue) RemoveTables(
-	ctx context.Context,
-	skipFKHandling bool,
-	allowDroppingFKReferenced bool,
-	originalTables ...doltdb.TableName,
+		ctx context.Context,
+		skipFKHandling bool,
+		allowDroppingFKReferenced bool,
+		originalTables ...doltdb.TableName,
 ) (doltdb.RootValue, error) {
 	if len(originalTables) == 0 {
 		return root, nil

server/ast/drop_schema.go

@@ -27,5 +27,17 @@ func nodeDropSchema(ctx *Context, node *tree.DropSchema) (vitess.Statement, erro
 		return nil, nil
 	}
 
-	return NotYetSupportedError("DROP SCHEMA is not yet supported")
+	if len(node.Names) > 1 {
+		return NotYetSupportedError("DROP SCHEMA with multiple schema names")
+	}
+
+	schemaName := node.Names[0]
+
+	return &vitess.DBDDL{
+		Action:           vitess.DropStr,
+		SchemaOrDatabase: "schema",
+		DBName:           schemaName,
+		CharsetCollate:   nil,
+		IfExists:         node.IfExists,
+	}, nil
 }