diff --git a/readme.md b/readme.md
index 197a59e..d023b05 100644
--- a/readme.md
+++ b/readme.md
@@ -1,4 +1,4 @@
 # DBlang
-sql Querys with js ot ts Syntax.
+sql Querys with js or ts Syntax.
 
 [![status-badge](https://ci.jusax.de/api/badges/jusax23/dblang/status.svg)](https://ci.jusax.de/jusax23/dblang)
\ No newline at end of file
diff --git a/src/db.ts b/src/db.ts
index b7187fd..5566360 100644
--- a/src/db.ts
+++ b/src/db.ts
@@ -1,37 +1,38 @@
 import mariadb from 'mariadb';
 import { checkConstraint, Constraint, Datatype, uniqueConstraint } from './dbStructure';
 import { Handler } from './defaultHandler';
-import { Query, selectQuery } from './query';
-import { attributeSettings, extendedAttributeSettings, onAction, primaryData, serializeReturn } from './types';
+import { Query } from './query';
+import { attributeSettings, extendedAttributeSettings, onAction } from './types';
 
 
 export class DB {
-    tables:Table[] = [];
+    tables: Table[] = [];
     handler: Handler;
     name: string;
-    //pool:mariadb.Pool;
-    constructor(/*{ host, user, password, database, connectionLimit = 5 }*/) {
-        //this.pool = mariadb.createPool({ host, user, password, database, connectionLimit, multipleStatements: true });
+    pool: mariadb.Pool;
+    constructor({ host, user, password, database, connectionLimit = 5 }: { host: string, user: string, password: string, database: string, connectionLimit: number }) {
+        this.pool = mariadb.createPool({ host, user, password, database, connectionLimit, multipleStatements: true });
         this.handler = new Handler();
-        this.name = "notimplemented"
+        this.name = database;
     }
     async query(query: Query) {
         console.log(query);
-        //return this.pool.query(query);
+        return await this.pool.query(query);
     }
     getHandler() {
         return this.handler;
     }
 
-    sync(){
+    async sync() {
         let handler = this.getHandler();
-        this.tables.forEach(t=>{
-            console.log(new Query(handler.builders.query(handler.querys.create(handler,t))));
-        })
+        await handler.syncDB(this, handler);
+        //this.tables.forEach(t=>{
+        //    console.log(handler.builders.query(handler.querys.create(handler,t)));
+        //})
     }
 
     newTable(name: string) {
-        let tabel = new Table(name,this);
+        let tabel = new Table(name, this);
         this.tables.push(tabel);
         return tabel;
     }
@@ -42,39 +43,40 @@ export class Attribute {
     table: Table;
     ops: attributeSettings;
     type: Datatype;
-    constructor(name: string, table:Table, type: Datatype, ops: attributeSettings) {
+    constructor(name: string, table: Table, type: Datatype, ops: attributeSettings) {
         this.name = name;
-        this.ops = ops;
         this.type = type;
         this.table = table;
-        
-        if(ops.check != null){
+        this.ops = ops;
+
+        if (ops.check != null) {
+            if(typeof ops.check == "function")ops.check = ops.check(this);
             table.addConstraint(new checkConstraint(
-                table.dbLangDatabaseInstance.name+"_"+table.dbLangTableName+"_"+name+"_check_constraint",
+                table.dbLangDatabaseInstance.name + "_" + table.dbLangTableName + "_" + name + "_check_constraint",
                 ops.check
             ))
         }
-        if(ops.unique != null){
+        if (ops.unique != null) {
             table.addConstraint(new uniqueConstraint(
-                table.dbLangDatabaseInstance.name+"_"+table.dbLangTableName+" "+name+"_unique_constraint",
+                table.dbLangDatabaseInstance.name + "_" + table.dbLangTableName + " " + name + "_unique_constraint",
                 [this]
             ))
         }
     }
-    serializeDatatype(handler : Handler){
+    serializeDatatype(handler: Handler) {
         return this.type.serialize(handler);
     }
-    serializeSettings(handler : Handler){
-        return handler.builders.attributeSettings(handler,this);
+    serializeSettings(handler: Handler) {
+        return handler.builders.attributeSettings(handler, this);
     }
-    serialize(handler : Handler) {
+    serialize(handler: Handler) {
         return handler.builders.escapeID(this.name);
     }
-    toString(handler : Handler = this.table.dbLangDatabaseInstance.getHandler()) {
-        return this.table.serialize(handler)+"."+this.serialize(handler);
+    toString(handler: Handler = this.table.dbLangDatabaseInstance.getHandler()) {
+        return this.table.serialize(handler) + "." + this.serialize(handler);
     }
-    toStringFunc(handler : Handler){
-        return this.table.serialize(handler)+"("+this.serialize(handler)+")";
+    toStringFunc(handler: Handler) {
+        return this.table.serialize(handler) + "(" + this.serialize(handler) + ")";
     }
 }
 
@@ -84,34 +86,34 @@ export class Table {
     dbLangTableAttributes: { [key: string]: Attribute; } = {};
     dbLangDatabaseInstance: DB;
     dbLangConstrains: Constraint[] = [];
-    [key: string]: Attribute | any
-    constructor(name: string, db:DB) {
+    [key: string]: Attribute | any;
+    constructor(name: string, db: DB) {
         this.dbLangTableName = name;
         this.dbLangDatabaseInstance = db;
     }
-    serialize(handler : Handler) {
+    serialize(handler: Handler) {
         return this.toString(handler);
     }
-    toString(handler : Handler = this.dbLangDatabaseInstance.getHandler()) {
+    toString(handler: Handler = this.dbLangDatabaseInstance.getHandler()) {
         return handler.builders.escapeID(this.dbLangTableName);
     }
     addAttribute(name: string, type: Datatype, ops: attributeSettings = {}, noErrorOnNameConflict = false) {
-        if(this.dbLangTableAttributes[name] != null) throw new Error("You are tring to create an Attribute twise!");
-        let attr = new Attribute(name,this,type,ops);
+        if (this.dbLangTableAttributes[name] != null) throw new Error("You are tring to create an Attribute twise!");
+        let attr = new Attribute(name, this, type, ops);
         this.dbLangTableAttributes[name] = attr;
-        if (["serialize", "toString", "addAttribute", "dbLangTableName", "dbLangTableAttributes", "dbLangDatabaseInstance","addConstraint","addAttributes"].includes(name)) {
+        if (["serialize", "toString", "addAttribute", "dbLangTableName", "dbLangTableAttributes", "dbLangDatabaseInstance", "addConstraint", "addAttributes"].includes(name)) {
             if (!noErrorOnNameConflict) throw new Error("You cannot name Attribute like Methode of this Table!");
         } else {
             this[name] = attr;
         }
         return attr;
     }
-    addAttributes(list:{[key: string]:extendedAttributeSettings}):{[key: string]:Attribute} {
-        return Object.fromEntries(Object.entries(list).map(([k,a])=>{
-            return [k,this.addAttribute(k,a.type,a)];
+    addAttributes(list: { [key: string]: (extendedAttributeSettings) }): { [key: string]: Attribute } {
+        return Object.fromEntries(Object.entries(list).map(([k, a]) => {
+            return [k, this.addAttribute(k, a.type, a)];
         }));
     }
-    addConstraint(c:Constraint){
+    addConstraint(c: Constraint) {
         c.check(this);
         this.dbLangConstrains.push(c);
     }
diff --git a/src/dbStructure.ts b/src/dbStructure.ts
index d3ecde2..b5fe4fd 100644
--- a/src/dbStructure.ts
+++ b/src/dbStructure.ts
@@ -64,7 +64,7 @@ export class checkConstraint implements Constraint{
         this.checkQuery = check;
     }
     check(attr: Table): boolean {
-        throw new Error("Method not implemented.");
+        return true;
     }
     uses(attr: Attribute): boolean {
         throw new Error("Method not implemented.");
@@ -76,19 +76,19 @@ export class checkConstraint implements Constraint{
 
 export class uniqueConstraint implements Constraint{
     name: string;
-    attr: Attribute[];
-    constructor(name:string, attr:Attribute[]){
+    attrs: Attribute[];
+    constructor(name:string, attrs:Attribute[]){
         this.name = name;
-        this.attr = attr;
+        this.attrs = attrs;
     }
     check(table: Table): boolean|string {
-        for(let i = 0; i < this.attr.length; i++){
-            if(this.attr[i].ops.primaryKey) return "Can not combine unique Constraint and primary key";
+        for(let i = 0; i < this.attrs.length; i++){
+            if(this.attrs[i].ops.primaryKey) return "Can not combine unique Constraint and primary key";
         }
         return false;
     }
     uses(attr: Attribute): boolean {
-        throw new Error("Method not implemented.");
+        return this.attrs.includes(attr);
     }
     serialize(handler: Handler): QueryBuilder {
         throw new Error("Method not implemented.");
diff --git a/src/defaultHandler.ts b/src/defaultHandler.ts
index 156ea49..9aa48af 100644
--- a/src/defaultHandler.ts
+++ b/src/defaultHandler.ts
@@ -1,12 +1,115 @@
 import { Attribute, DB, Table } from "./db"
-import { Aggregation, Modifier } from "./dbStructure"
-import { QueryBuilder, selectQuery } from "./query"
+import { Aggregation, checkConstraint, Constraint, Datatype, Modifier, uniqueConstraint } from "./dbStructure"
+import { Query, QueryBuilder, selectQuery } from "./query"
 import { allModifierInput, primaryData, serializeReturn } from "./types"
 
 export class Handler {
-    /*syncDB(db : DB){
+    async syncDB(db: DB, handler: Handler, deleteInDB: boolean = false) {
+        console.log("start sync");
 
-    }*/
+        let gd = new QueryBuilder();
+        gd.addCode(`SELECT * FROM INFORMATION_SCHEMA.KEY_COLUMN_USAGE where CONSTRAINT_SCHEMA = `);
+        gd.addInjection(db.name);
+        gd.addCode(` or TABLE_SCHEMA = `);
+        gd.addInjection(db.name);
+        gd.addCode(`;select * from information_schema.table_constraints where CONSTRAINT_SCHEMA = `);
+        gd.addInjection(db.name)
+        gd.addCode(` or TABLE_SCHEMA = `);
+        gd.addInjection(db.name);
+
+        let [key, constraints] = await db.query(handler.builders.query(gd));
+
+
+        let tableData = [];
+        for (let i = 0; i < db.tables.length; i++) {
+            const table = db.tables[i];
+            try {
+                const tableDataBuilder = new QueryBuilder();
+                tableDataBuilder.addCode("DESCRIBE ");
+                tableDataBuilder.addCode(table.serialize(handler));
+                tableData[i] = Object.fromEntries((await db.query(handler.builders.query(tableDataBuilder))).map((d: any) => [d.Field, d]));
+            } catch (_) {
+                tableData[i] = null;
+            }
+        }
+
+        const del = new QueryBuilder();
+        const create = new QueryBuilder();
+
+        for (let i = 0; i < constraints.length; i++) {
+            const c = constraints[i];
+            if (c.CONSTRAINT_TYPE == "CHECK") {
+                del.appendEnding(handler.querys.removeCheck(handler, c.TABLE_NAME, c.CONSTRAINT_NAME));
+            }
+        }
+        // TODO: delete old constraints/tables
+
+        function freeForUpdate(a: Attribute) {
+            for (let i = 0; i < key.length; i++) {
+                const k = key[i];
+                if (
+                    k.REFERENCED_TABLE_NAME == a.table.dbLangTableName
+                    && k.REFERENCED_TABLE_NAME == a.name
+                ) {
+                    del.appendEnding(handler.querys.removeForeignKey(handler, k.TABLE_NAME, k.CONSTRAINT_NAME));
+                }
+            }
+        }
+
+        //create tables
+        for (let i = 0; i < db.tables.length; i++) {
+            const table = db.tables[i];
+            const tableD = tableData[i];
+            let changePrimary = false;
+            if (tableD == null) {
+                create.appendEnding(handler.querys.create(handler, table));
+                changePrimary = true;
+            } else {
+                let keys = Object.keys(table.dbLangTableAttributes);
+                for (let j = 0; j < keys.length; j++) {
+                    const a = table.dbLangTableAttributes[keys[j]];
+                    const attrData = tableD[keys[j]];
+                    if (attrData == null) {
+                        create.appendEnding(handler.querys.addColumn(handler, a));
+                        changePrimary = true;
+                    } else if (
+                        !handler.builders.compareDatatypes(handler, a.type, attrData.Type) ||
+                        a.ops.default != attrData.Default ||
+                        (!!a.ops.notNull || !!a.ops.autoIncrement || !!a.ops.primaryKey) != (attrData.Null == "NO") ||
+                        (!!a.ops.autoIncrement) != (attrData.Extra == "auto_increment")
+                    ) {
+                        console.log(!handler.builders.compareDatatypes(handler, a.type, attrData.Type), "|",
+                            a.ops.default, attrData.Default, "|",
+                            (!!a.ops.notNull || !!a.ops.autoIncrement || !!a.ops.primaryKey), (attrData.Null == "NO"), "|",
+                            (!!a.ops.autoIncrement), (attrData.Extra == "auto_increment"));
+                        freeForUpdate(a);
+                        create.appendEnding(handler.querys.changeColumn(handler, a));
+                    }
+                    if (attrData == null) {
+                        changePrimary = true;
+                    } else {
+                        if ((attrData.Key == "PRI") != (!!a.ops.primaryKey)) {
+                            freeForUpdate(a);
+                            changePrimary = true;
+                        }
+                    }
+                }
+            }
+            if (changePrimary) {
+                create.appendEnding(handler.querys.removePrimaryKey(handler, table));
+                create.appendEnding(handler.querys.addPrimaryKey(handler, table));
+            }
+            for (let j = 0; j < table.dbLangConstrains.length; j++) {
+                const c = table.dbLangConstrains[j];
+                if (c instanceof checkConstraint) {
+                    create.appendEnding(handler.querys.addCheck(handler, table, c));
+                }
+            }
+            // TODO: unique
+        }
+        if (!create.isEmpty()) del.append(create);
+        if (!del.isEmpty()) await db.query(handler.builders.query(del));
+    }
 
     querys = {
         select: (handler: Handler, q: selectQuery): QueryBuilder => {
@@ -26,11 +129,15 @@ export class Handler {
                     builder.append(q.havingD.serialize(handler));
                 }
             }
-
             if (q.havingD) {
                 builder.addCode(" limit ");
                 builder.addInjection(q.limitD);
             }
+
+            /*builder.setHandler((json)=>{
+                return json;
+            });*/
+
             return builder;
         },
         create: (handler: Handler, table: Table): QueryBuilder => {
@@ -46,16 +153,102 @@ export class Handler {
             builder.addCode(")");
             return builder;
         },
+        addColumn: (handler: Handler, attr: Attribute): QueryBuilder => {
+            const builder = new QueryBuilder();
+            builder.addCode(`alter table `);
+            builder.addCode(attr.table.toString(handler));
+            builder.addCode(` add if not exists `);
+            builder.addCode(attr.serialize(handler) + " ");
+            builder.append(attr.serializeSettings(handler));
+            return builder;
+        },
+        changeColumn: (handler: Handler, attr: Attribute): QueryBuilder => {
+            const builder = new QueryBuilder();
+            builder.addCode(`alter table `);
+            builder.addCode(attr.table.toString(handler));
+            builder.addCode(` change `);
+            builder.addCode(attr.serialize(handler) + " ");
+            builder.addCode(attr.serialize(handler) + " ");
+            builder.append(attr.serializeSettings(handler));
+            return builder;
+        },
+        addForeignKey: (handler: Handler, table: Table) => {
+            const builder = new QueryBuilder();
 
-    }
+            return builder;
+        },
+        removeForeignKey: (handler: Handler, tablenName: string, name: string) => {
+            const builder = new QueryBuilder();
+            builder.addCode("ALTER TABLE ");
+            builder.addCode(handler.builders.escapeID(tablenName));
+            builder.addCode(" DROP FOREIGN KEY IF EXISTS ");
+            builder.addCode(handler.builders.escapeID(name));
+            builder.addCode(";ALTER TABLE ");
+            builder.addCode(handler.builders.escapeID(tablenName));
+            builder.addCode(" DROP INDEX IF EXISTS ");
+            builder.addCode(handler.builders.escapeID(name));
 
-    constraints = {
-        // check constraints
-        listPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
-        listForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
-        listUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
-        listChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
-        // add constraints
+            return builder;
+        },
+        addPrimaryKey: (handler: Handler, table: Table) => {
+            const qb = new QueryBuilder();
+            qb.addCode("ALTER TABLE ");
+            qb.addCode(table.serialize(handler));
+            qb.addCode(" add PRIMARY KEY if not exists (");
+            qb.addCodeCommaSeperated(
+                Object.entries(table.dbLangTableAttributes)
+                    .filter(([n, attr]) => !!attr.ops.primaryKey)
+                    .map(([n, attr]) => handler.builders.escapeID(n))
+            );
+            qb.addCode(")");
+            return qb;
+        },
+        removePrimaryKey: (handler: Handler, table: Table) => {
+            const qb = new QueryBuilder();
+            qb.addCode("ALTER TABLE ");
+            qb.addCode(table.serialize(handler));
+            qb.addCode(" DROP INDEX IF EXISTS `PRIMARY`");
+            return qb;
+        },
+        removeCheck: (handler: Handler, table: string, name: string) => {
+            const qb = new QueryBuilder();
+            qb.addCode("ALTER TABLE ");
+            qb.addCode(handler.builders.escapeID(table));
+            qb.addCode(" DROP CONSTRAINT IF EXISTS ");
+            qb.addCode(handler.builders.escapeID(name));
+            return qb;
+        },
+        addCheck: (handler: Handler, table: Table, c: checkConstraint) => {
+            const qb = new QueryBuilder();
+            qb.addCode(`ALTER TABLE `);
+            qb.addCode(table.serialize(handler));
+            qb.addCode(` ADD CONSTRAINT `);
+            qb.addCode(handler.builders.escapeID(c.name));
+            qb.addCode(` CHECK (`);
+            qb.append(c.checkQuery.serialize(handler));
+            qb.addCode(")");
+            return qb;
+        },
+        removeUnique: (handler: Handler, table: string, name: string) => {
+            const qb = new QueryBuilder();
+            qb.addCode("ALTER TABLE ");
+            qb.addCode(handler.builders.escapeID(table));
+            qb.addCode(" DROP INDEX IF EXISTS ");
+            qb.addCode(handler.builders.escapeID(name));
+            return qb;
+        },
+        addUnique: (handler: Handler, table: Table, u: uniqueConstraint) => {
+            const qb = new QueryBuilder();
+            qb.addCode("ALTER TABLE ");
+            qb.addCode(table.serialize(handler));
+            qb.addCode(" ADD CONSTRAINT ");
+            qb.addCode(handler.builders.escapeID(u.name));
+            qb.addCode(" UNIQUE (");
+            qb.addCodeCommaSeperated(u.attrs.map(a => a.serialize(handler)));
+            qb.addCode(")");
+            return qb;
+        },
+        /*// add constraints
         appPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
         appForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
         addUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
@@ -65,10 +258,15 @@ export class Handler {
         dropForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
         dropUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
         dropChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
+        // check constraints
+        listPrimaryKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
+        listForeignKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
+        listUniqueKeys: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),
+        listChecks: (handler: Handler, table: Table): QueryBuilder => new QueryBuilder(),*/
     }
 
     builders = {
-        query: (qb: QueryBuilder): serializeReturn => {
+        query: (qb: QueryBuilder): Query => {
             let args: primaryData[] = [];
             let sql = "";
             for (let i = 0; i < qb.list.length; i++) {
@@ -80,7 +278,7 @@ export class Handler {
                     sql += data;
                 }
             }
-            return [sql, args];
+            return new Query([sql, args]);
         },
 
         attributeSettings: (handler: Handler, a: Attribute): QueryBuilder => {
@@ -89,38 +287,34 @@ export class Handler {
             if (a.ops.autoIncrement) {
                 builder.addCode(" auto_increment");
             }
-            /*if (a.ops.primaryKey) {
-                sql += " primary key";
-            }*/
             if (a.ops.default != null) {
                 if (a.ops.autoIncrement || a.ops.primaryKey || a.ops.notNull)
                     throw new Error(`Can not set default when autoIncrement, primaryKey or notNull ist set on Attribute: ${a.toStringFunc(handler)}`);
                 builder.addCode(" default ");
                 builder.addInjection(a.ops.default);
             }
-
-            /*if (a.ops.unique != null) {
-                if (!a.ops.autoIncrement && !a.ops.primaryKey){
-                    sql += " unique";
-                }
-            }*/
             if (a.ops.notNull != null) {
                 if (!a.ops.autoIncrement && !a.ops.primaryKey && a.ops.default == null) {
                     builder.addCode(" not null");
-                }
-            }
-
-            /*if (a.ops.foreginKey != null) {
-                sql += ` foreign key references (${a.ops.foreginKey.link.toStringFunc(handler)})`
-            }*/
-
+                } else builder.addCode(" null");
+            } else builder.addCode(" null");
             return builder;
         },
         escapeID: (key: string): string => {
             if (!key || key === "" || key.includes('\u0000')) throw new Error("Can not escape empty key or with null unicode!");
             if (key.match(/^`.+`$/g)) return key;
             return `\`${key.replace(/`/g, '``')}\``;
-        }
+        },
+        compareDatatypes: (handler: Handler, attr: Datatype, curr: String) => {
+            let qb = attr.serialize(handler);
+            let sql = "";
+            for (let i = 0; i < qb.list.length; i++) {
+                const [inject, data] = qb.list[i];
+                sql += data;
+            }
+
+            return curr.split(" ").join("").startsWith(sql.split(" ").join(""));
+        },
     }
 
 
@@ -200,7 +394,7 @@ export class Handler {
         double: dataTypeDblNum("double"),
         decimal: dataTypeDblNum("decimal"),
 
-        date: dataTypeNoArg("data"),
+        date: dataTypeNoArg("date"),
         datetime: dataTypeNoArg("datatime"),
         timestamp: dataTypeNoArg("timestamp"),
         time: dataTypeNoArg("time"),
diff --git a/src/query.ts b/src/query.ts
index 4cf4e16..3debfff 100644
--- a/src/query.ts
+++ b/src/query.ts
@@ -16,6 +16,7 @@ export class Query {
 export class QueryBuilder {
     //injekt and data
     list: ([boolean, primaryData])[] = [];
+    
     constructor(l?: ({ inject?: boolean, data: primaryData })[]) {
         if (Array.isArray(l))
             for (let i = 0; i < l.length; i++) {
@@ -26,6 +27,13 @@ export class QueryBuilder {
     addCode(text: string) {
         this.list.push([false, text]);
     }
+    addCodeCommaSeperated(data: string[], comma = ", ") {
+        for (let i = 0; i < data.length; i++) {
+            const e = data[i];
+            this.list.push([false, e]);
+            if(i+1<data.length)this.list.push([false, comma]);
+        }
+    }
     addInjection(data: primaryData) {
         this.list.push([true, data]);
     }
@@ -39,6 +47,16 @@ export class QueryBuilder {
     append(qb: QueryBuilder) {
         this.list.push(...qb.list);
     }
+    appendEnding(qb: QueryBuilder){
+        this.append(qb);
+        this.list.push([false,";"]);
+    }
+    isEmpty(){
+        return this.list.length == 0;
+    }
+    /*setHandler(fun:(d:any)=>any){
+
+    }*/
 }
 
 
@@ -74,9 +92,10 @@ export class selectQuery {
         return handler.querys.select(handler, this);
     }
 
-    query(db: DB) {
+    async query(db: DB) {
         const handler = db.getHandler();
-        const s = handler.builders.query(this.serialize(handler));
-        return db.query(new Query(s));
+        const builder = this.serialize(handler);
+        const s = handler.builders.query(builder);
+        return await db.query(s);
     }
 }
\ No newline at end of file
diff --git a/src/types.ts b/src/types.ts
index e0f6ea7..c7bc431 100644
--- a/src/types.ts
+++ b/src/types.ts
@@ -1,6 +1,6 @@
 import { Attribute, Table } from "./db";
 import { Aggregation, BooleanModifier, Datatype, Joins, Modifier } from "./dbStructure";
-import { selectQuery } from "./query";
+import { QueryBuilder, selectQuery } from "./query";
 
 export type primaryData = string | number | boolean | null;
 export type allModifierInput = primaryData | Modifier | selectQuery | Attribute | Aggregation;
@@ -10,6 +10,8 @@ export type selectFromElements = Table | Joins | null;
 
 export type serializeReturn = [string, primaryData[]];
 
+export type DatatypeBuild = [QueryBuilder, number];
+
 export type attributeSettings = {
     unique?: boolean,
     autoIncrement?: boolean,
@@ -21,8 +23,9 @@ export type attributeSettings = {
         onDelete?: onAction,
         onUpdate?: onAction
     },
-    check?:BooleanModifier
+    check?: BooleanModifier | ((a: Attribute) => BooleanModifier)
 };
+
 export type extendedAttributeSettings = {
     type: Datatype,
     unique?: boolean,
@@ -35,7 +38,7 @@ export type extendedAttributeSettings = {
         onDelete?: onAction,
         onUpdate?: onAction
     },
-    check?:BooleanModifier
+    check?: BooleanModifier | ((a: Attribute) => BooleanModifier)
 }
 
 export enum onAction {