Added setNullable support to SQLite

lib/dialects/sqlite3/schema/ddl.js

@@ -344,6 +344,40 @@ class SQLite3_DDL {
     );
   }
 
+  setNullable(column, isNullable) {
+    return this.client.transaction(
+      async (trx) => {
+        this.trx = trx;
+
+        const { createTable, createIndices } = await this.getTableSql();
+
+        const parsedTable = parseCreateTable(createTable);
+        const parsedColumn = parsedTable.columns.find((c) =>
+          isEqualId(column, c.name)
+        );
+
+        if (!parsedColumn) {
+          throw new Error(
+            `.setNullable: Column ${column} does not exist in table ${this.tableName()}.`
+          );
+        }
+
+        parsedColumn.constraints.notnull = isNullable
+          ? null
+          : { name: null, conflict: null };
+
+        parsedColumn.constraints.null = isNullable
+          ? parsedColumn.constraints.null
+          : null;
+
+        const newTable = compileCreateTable(parsedTable, this.wrap);
+
+        return this.alter(newTable, createIndices);
+      },
+      { connection: this.connection }
+    );
+  }
+
   async alter(newSql, createIndices, columns) {
     await this.createNewTable(newSql);
     await this.copyData(columns);

lib/dialects/sqlite3/schema/sqlite-tablecompiler.js

@@ -266,8 +266,16 @@ class TableCompiler_SQLite3 extends TableCompiler {
   }
 
   _setNullableState(column, isNullable) {
-    const fnCalled = isNullable ? '.setNullable' : '.dropNullable';
-    throw new Error(`${fnCalled} is not supported for SQLite.`);
+    const compiler = this;
+
+    this.pushQuery({
+      sql: `PRAGMA table_info(${this.tableName()})`,
+      output(pragma) {
+        return compiler.client
+          .ddl(compiler, pragma, this.connection)
+          .setNullable(column, isNullable);
+      },
+    });
   }
 
   dropColumn() {

test/integration2/schema/set-nullable.spec.js

@@ -17,9 +17,6 @@ describe('Schema', () => {
 
         before(function () {
           knex = getKnexForDb(db);
-          if (isSQLite(knex)) {
-            return this.skip();
-          }
         });
 
         after(() => {
@@ -63,6 +60,9 @@ describe('Schema', () => {
               errorMessage = 'cannot be null';
             } else if (isOracle(knex)) {
               errorMessage = 'ORA-01400: cannot insert NULL into';
+            } else if (isSQLite(knex)) {
+              errorMessage =
+                'insert into `primary_table` (`id_not_nullable`, `id_nullable`) values (1, NULL) - SQLITE_CONSTRAINT: NOT NULL constraint failed: primary_table.id_nullable';
             }
 
             await expect(