diff --git a/src/shared/services/base.service.ts b/src/shared/services/base.service.ts
index 7a2763c..e368b92 100644
--- a/src/shared/services/base.service.ts
+++ b/src/shared/services/base.service.ts
@@ -1,415 +1,429 @@
-import {
-  Repository,
-  FindOptionsWhere,
-  FindOptionsOrder,
-  FindOptionsRelations,
-  SelectQueryBuilder,
-  DeepPartial,
-  In,
-} from 'typeorm';
-import {
-  PaginationParams,
-  PaginatedResult,
-  FilterCondition,
-  QueryOptions,
-  ServiceResult,
-} from '../types';
+import { query, queryOne, getClient, PoolClient } from '../../config/database.js';
+import { NotFoundError, ValidationError } from '../errors/index.js';
+import { PaginationMeta } from '../types/index.js';
 
-export abstract class BaseService<T extends { id: string; tenantId: string }> {
-  constructor(protected readonly repository: Repository<T>) {}
+/**
+ * Resultado paginado genérico
+ */
+export interface PaginatedResult<T> {
+  data: T[];
+  total: number;
+  page: number;
+  limit: number;
+  totalPages: number;
+}
+
+/**
+ * Filtros de paginación base
+ */
+export interface BasePaginationFilters {
+  page?: number;
+  limit?: number;
+  sortBy?: string;
+  sortOrder?: 'asc' | 'desc';
+  search?: string;
+}
+
+/**
+ * Opciones para construcción de queries
+ */
+export interface QueryOptions {
+  client?: PoolClient;
+  includeDeleted?: boolean;
+}
+
+/**
+ * Configuración del servicio base
+ */
+export interface BaseServiceConfig {
+  tableName: string;
+  schema: string;
+  selectFields: string;
+  searchFields?: string[];
+  defaultSortField?: string;
+  softDelete?: boolean;
+}
+
+/**
+ * Clase base abstracta para servicios CRUD con soporte multi-tenant
+ *
+ * Proporciona implementaciones reutilizables para:
+ * - Paginación con filtros
+ * - Búsqueda por texto
+ * - CRUD básico
+ * - Soft delete
+ * - Transacciones
+ *
+ * @example
+ * ```typescript
+ * class PartnersService extends BaseService<Partner, CreatePartnerDto, UpdatePartnerDto> {
+ *   protected config: BaseServiceConfig = {
+ *     tableName: 'partners',
+ *     schema: 'core',
+ *     selectFields: 'id, tenant_id, name, email, phone, created_at',
+ *     searchFields: ['name', 'email', 'tax_id'],
+ *     defaultSortField: 'name',
+ *     softDelete: true,
+ *   };
+ * }
+ * ```
+ */
+export abstract class BaseService<T, CreateDto, UpdateDto> {
+  protected abstract config: BaseServiceConfig;
 
   /**
-   * Find all entities for a tenant with optional pagination and filters
+   * Nombre completo de la tabla (schema.table)
+   */
+  protected get fullTableName(): string {
+    return `${this.config.schema}.${this.config.tableName}`;
+  }
+
+  /**
+   * Obtiene todos los registros con paginación y filtros
    */
   async findAll(
     tenantId: string,
-    options?: QueryOptions
+    filters: BasePaginationFilters & Record<string, any> = {},
+    options: QueryOptions = {}
   ): Promise<PaginatedResult<T>> {
     const {
-      pagination = { page: 1, limit: 20 },
-      filters = [],
+      page = 1,
+      limit = 20,
+      sortBy = this.config.defaultSortField || 'created_at',
+      sortOrder = 'desc',
       search,
-      relations = [],
-      select,
-    } = options || {};
+      ...customFilters
+    } = filters;
 
-    const queryBuilder = this.repository.createQueryBuilder('entity');
+    const offset = (page - 1) * limit;
+    const params: any[] = [tenantId];
+    let paramIndex = 2;
 
-    // Always filter by tenant
-    queryBuilder.where('entity.tenantId = :tenantId', { tenantId });
+    // Construir WHERE clause
+    let whereClause = 'WHERE tenant_id = $1';
 
-    // Apply filters
-    this.applyFilters(queryBuilder, filters);
+    // Soft delete
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
 
-    // Apply search
-    if (search && search.term && search.fields.length > 0) {
-      const searchConditions = search.fields
-        .map((field, index) => `entity.${field} ILIKE :search${index}`)
+    // Búsqueda por texto
+    if (search && this.config.searchFields?.length) {
+      const searchConditions = this.config.searchFields
+        .map(field => `${field} ILIKE $${paramIndex}`)
         .join(' OR ');
-
-      const searchParams: Record<string, string> = {};
-      search.fields.forEach((_, index) => {
-        searchParams[`search${index}`] = `%${search.term}%`;
-      });
-
-      queryBuilder.andWhere(`(${searchConditions})`, searchParams);
+      whereClause += ` AND (${searchConditions})`;
+      params.push(`%${search}%`);
+      paramIndex++;
     }
 
-    // Apply relations
-    relations.forEach((relation) => {
-      queryBuilder.leftJoinAndSelect(`entity.${relation}`, relation);
-    });
-
-    // Apply select
-    if (select && select.length > 0) {
-      queryBuilder.select(select.map((s) => `entity.${s}`));
+    // Filtros custom
+    for (const [key, value] of Object.entries(customFilters)) {
+      if (value !== undefined && value !== null && value !== '') {
+        whereClause += ` AND ${key} = $${paramIndex++}`;
+        params.push(value);
+      }
     }
 
-    // Get total count before pagination
-    const total = await queryBuilder.getCount();
+    // Validar sortBy para prevenir SQL injection
+    const safeSortBy = this.sanitizeFieldName(sortBy);
+    const safeSortOrder = sortOrder === 'asc' ? 'ASC' : 'DESC';
 
-    // Apply sorting
-    const sortBy = pagination.sortBy || 'createdAt';
-    const sortOrder = pagination.sortOrder || 'DESC';
-    queryBuilder.orderBy(`entity.${sortBy}`, sortOrder);
+    // Query de conteo
+    const countSql = `
+      SELECT COUNT(*) as count
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
 
-    // Apply pagination
-    const skip = (pagination.page - 1) * pagination.limit;
-    queryBuilder.skip(skip).take(pagination.limit);
+    // Query de datos
+    const dataSql = `
+      SELECT ${this.config.selectFields}
+      FROM ${this.fullTableName}
+      ${whereClause}
+      ORDER BY ${safeSortBy} ${safeSortOrder}
+      LIMIT $${paramIndex++} OFFSET $${paramIndex}
+    `;
 
-    const data = await queryBuilder.getMany();
+    if (options.client) {
+      const [countResult, dataResult] = await Promise.all([
+        options.client.query(countSql, params),
+        options.client.query(dataSql, [...params, limit, offset]),
+      ]);
 
-    const totalPages = Math.ceil(total / pagination.limit);
+      const total = parseInt(countResult.rows[0]?.count || '0', 10);
+
+      return {
+        data: dataResult.rows as T[],
+        total,
+        page,
+        limit,
+        totalPages: Math.ceil(total / limit),
+      };
+    }
+
+    const [countRows, dataRows] = await Promise.all([
+      query<{ count: string }>(countSql, params),
+      query<T>(dataSql, [...params, limit, offset]),
+    ]);
+
+    const total = parseInt(countRows[0]?.count || '0', 10);
 
     return {
-      data,
-      pagination: {
-        page: pagination.page,
-        limit: pagination.limit,
-        total,
-        totalPages,
-        hasNext: pagination.page < totalPages,
-        hasPrev: pagination.page > 1,
-      },
+      data: dataRows,
+      total,
+      page,
+      limit,
+      totalPages: Math.ceil(total / limit),
     };
   }
 
   /**
-   * Find one entity by ID
+   * Obtiene un registro por ID
    */
   async findById(
-    tenantId: string,
     id: string,
-    relations?: string[]
+    tenantId: string,
+    options: QueryOptions = {}
   ): Promise<T | null> {
-    const where = { tenantId, id } as FindOptionsWhere<T>;
-    const relationsOption = relations
-      ? (relations.reduce((acc, rel) => ({ ...acc, [rel]: true }), {}) as FindOptionsRelations<T>)
-      : undefined;
+    let whereClause = 'WHERE id = $1 AND tenant_id = $2';
 
-    return this.repository.findOne({
-      where,
-      relations: relationsOption,
-    });
-  }
-
-  /**
-   * Find entities by a specific field
-   */
-  async findBy(
-    tenantId: string,
-    field: keyof T,
-    value: any,
-    relations?: string[]
-  ): Promise<T[]> {
-    const where = { tenantId, [field]: value } as FindOptionsWhere<T>;
-    const relationsOption = relations
-      ? (relations.reduce((acc, rel) => ({ ...acc, [rel]: true }), {}) as FindOptionsRelations<T>)
-      : undefined;
-
-    return this.repository.find({
-      where,
-      relations: relationsOption,
-    });
-  }
-
-  /**
-   * Find one entity by a specific field
-   */
-  async findOneBy(
-    tenantId: string,
-    field: keyof T,
-    value: any,
-    relations?: string[]
-  ): Promise<T | null> {
-    const where = { tenantId, [field]: value } as FindOptionsWhere<T>;
-    const relationsOption = relations
-      ? (relations.reduce((acc, rel) => ({ ...acc, [rel]: true }), {}) as FindOptionsRelations<T>)
-      : undefined;
-
-    return this.repository.findOne({
-      where,
-      relations: relationsOption,
-    });
-  }
-
-  /**
-   * Create a new entity
-   */
-  async create(
-    tenantId: string,
-    data: DeepPartial<T>,
-    userId?: string
-  ): Promise<ServiceResult<T>> {
-    try {
-      const entity = this.repository.create({
-        ...data,
-        tenantId,
-        createdBy: userId,
-        updatedBy: userId,
-      } as DeepPartial<T>);
-
-      const saved = await this.repository.save(entity);
-      return { success: true, data: saved };
-    } catch (error: any) {
-      return {
-        success: false,
-        error: {
-          code: 'CREATE_FAILED',
-          message: error.message || 'Failed to create entity',
-          details: error,
-        },
-      };
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
     }
-  }
 
-  /**
-   * Create multiple entities
-   */
-  async createMany(
-    tenantId: string,
-    dataArray: DeepPartial<T>[],
-    userId?: string
-  ): Promise<ServiceResult<T[]>> {
-    try {
-      const entities = dataArray.map((data) =>
-        this.repository.create({
-          ...data,
-          tenantId,
-          createdBy: userId,
-          updatedBy: userId,
-        } as DeepPartial<T>)
-      );
+    const sql = `
+      SELECT ${this.config.selectFields}
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
 
-      const saved = await this.repository.save(entities);
-      return { success: true, data: saved };
-    } catch (error: any) {
-      return {
-        success: false,
-        error: {
-          code: 'CREATE_MANY_FAILED',
-          message: error.message || 'Failed to create entities',
-          details: error,
-        },
-      };
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows[0] as T || null;
     }
+    const rows = await query<T>(sql, [id, tenantId]);
+    return rows[0] || null;
   }
 
   /**
-   * Update an entity
+   * Obtiene un registro por ID o lanza error si no existe
    */
-  async update(
-    tenantId: string,
+  async findByIdOrFail(
     id: string,
-    data: DeepPartial<T>,
-    userId?: string
-  ): Promise<ServiceResult<T>> {
-    try {
-      const existing = await this.findById(tenantId, id);
-      if (!existing) {
-        return {
-          success: false,
-          error: {
-            code: 'NOT_FOUND',
-            message: 'Entity not found',
-          },
-        };
-      }
-
-      const updated = this.repository.merge(existing, {
-        ...data,
-        updatedBy: userId,
-      } as DeepPartial<T>);
-
-      const saved = await this.repository.save(updated);
-      return { success: true, data: saved };
-    } catch (error: any) {
-      return {
-        success: false,
-        error: {
-          code: 'UPDATE_FAILED',
-          message: error.message || 'Failed to update entity',
-          details: error,
-        },
-      };
-    }
-  }
-
-  /**
-   * Delete an entity (soft delete if entity has deletedAt field)
-   */
-  async delete(tenantId: string, id: string): Promise<ServiceResult<boolean>> {
-    try {
-      const existing = await this.findById(tenantId, id);
-      if (!existing) {
-        return {
-          success: false,
-          error: {
-            code: 'NOT_FOUND',
-            message: 'Entity not found',
-          },
-        };
-      }
-
-      await this.repository.remove(existing);
-      return { success: true, data: true };
-    } catch (error: any) {
-      return {
-        success: false,
-        error: {
-          code: 'DELETE_FAILED',
-          message: error.message || 'Failed to delete entity',
-          details: error,
-        },
-      };
-    }
-  }
-
-  /**
-   * Delete multiple entities by IDs
-   */
-  async deleteMany(
     tenantId: string,
-    ids: string[]
-  ): Promise<ServiceResult<number>> {
-    try {
-      const result = await this.repository.delete({
-        tenantId,
-        id: In(ids),
-      } as FindOptionsWhere<T>);
-
-      return { success: true, data: result.affected || 0 };
-    } catch (error: any) {
-      return {
-        success: false,
-        error: {
-          code: 'DELETE_MANY_FAILED',
-          message: error.message || 'Failed to delete entities',
-          details: error,
-        },
-      };
+    options: QueryOptions = {}
+  ): Promise<T> {
+    const entity = await this.findById(id, tenantId, options);
+    if (!entity) {
+      throw new NotFoundError(`${this.config.tableName} with id ${id} not found`);
     }
+    return entity;
   }
 
   /**
-   * Check if entity exists
+   * Verifica si existe un registro
    */
-  async exists(tenantId: string, id: string): Promise<boolean> {
-    const count = await this.repository.count({
-      where: { tenantId, id } as FindOptionsWhere<T>,
-    });
-    return count > 0;
+  async exists(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    let whereClause = 'WHERE id = $1 AND tenant_id = $2';
+
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
+    }
+
+    const sql = `
+      SELECT 1 FROM ${this.fullTableName}
+      ${whereClause}
+      LIMIT 1
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId]);
+    return rows.length > 0;
   }
 
   /**
-   * Count entities matching criteria
+   * Soft delete de un registro
+   */
+  async softDelete(
+    id: string,
+    tenantId: string,
+    userId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    if (!this.config.softDelete) {
+      throw new ValidationError('Soft delete not enabled for this entity');
+    }
+
+    const sql = `
+      UPDATE ${this.fullTableName}
+      SET deleted_at = CURRENT_TIMESTAMP,
+          deleted_by = $3,
+          updated_at = CURRENT_TIMESTAMP
+      WHERE id = $1 AND tenant_id = $2 AND deleted_at IS NULL
+      RETURNING id
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId, userId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId, userId]);
+    return rows.length > 0;
+  }
+
+  /**
+   * Hard delete de un registro
+   */
+  async hardDelete(
+    id: string,
+    tenantId: string,
+    options: QueryOptions = {}
+  ): Promise<boolean> {
+    const sql = `
+      DELETE FROM ${this.fullTableName}
+      WHERE id = $1 AND tenant_id = $2
+      RETURNING id
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, [id, tenantId]);
+      return result.rows.length > 0;
+    }
+    const rows = await query(sql, [id, tenantId]);
+    return rows.length > 0;
+  }
+
+  /**
+   * Cuenta registros con filtros
    */
   async count(
     tenantId: string,
-    filters?: FilterCondition[]
+    filters: Record<string, any> = {},
+    options: QueryOptions = {}
   ): Promise<number> {
-    const queryBuilder = this.repository.createQueryBuilder('entity');
-    queryBuilder.where('entity.tenantId = :tenantId', { tenantId });
+    const params: any[] = [tenantId];
+    let paramIndex = 2;
+    let whereClause = 'WHERE tenant_id = $1';
 
-    if (filters) {
-      this.applyFilters(queryBuilder, filters);
+    if (this.config.softDelete && !options.includeDeleted) {
+      whereClause += ' AND deleted_at IS NULL';
     }
 
-    return queryBuilder.getCount();
+    for (const [key, value] of Object.entries(filters)) {
+      if (value !== undefined && value !== null) {
+        whereClause += ` AND ${key} = $${paramIndex++}`;
+        params.push(value);
+      }
+    }
+
+    const sql = `
+      SELECT COUNT(*) as count
+      FROM ${this.fullTableName}
+      ${whereClause}
+    `;
+
+    if (options.client) {
+      const result = await options.client.query(sql, params);
+      return parseInt(result.rows[0]?.count || '0', 10);
+    }
+    const rows = await query<{ count: string }>(sql, params);
+    return parseInt(rows[0]?.count || '0', 10);
   }
 
   /**
-   * Apply filter conditions to query builder
+   * Ejecuta una función dentro de una transacción
    */
-  protected applyFilters(
-    queryBuilder: SelectQueryBuilder<T>,
-    filters: FilterCondition[]
-  ): void {
-    filters.forEach((filter, index) => {
-      const paramName = `filter${index}`;
+  protected async withTransaction<R>(
+    fn: (client: PoolClient) => Promise<R>
+  ): Promise<R> {
+    const client = await getClient();
+    try {
+      await client.query('BEGIN');
+      const result = await fn(client);
+      await client.query('COMMIT');
+      return result;
+    } catch (error) {
+      await client.query('ROLLBACK');
+      throw error;
+    } finally {
+      client.release();
+    }
+  }
 
-      switch (filter.operator) {
-        case 'eq':
-          queryBuilder.andWhere(`entity.${filter.field} = :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'ne':
-          queryBuilder.andWhere(`entity.${filter.field} != :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'gt':
-          queryBuilder.andWhere(`entity.${filter.field} > :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'gte':
-          queryBuilder.andWhere(`entity.${filter.field} >= :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'lt':
-          queryBuilder.andWhere(`entity.${filter.field} < :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'lte':
-          queryBuilder.andWhere(`entity.${filter.field} <= :${paramName}`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'like':
-          queryBuilder.andWhere(`entity.${filter.field} LIKE :${paramName}`, {
-            [paramName]: `%${filter.value}%`,
-          });
-          break;
-        case 'ilike':
-          queryBuilder.andWhere(`entity.${filter.field} ILIKE :${paramName}`, {
-            [paramName]: `%${filter.value}%`,
-          });
-          break;
-        case 'in':
-          queryBuilder.andWhere(`entity.${filter.field} IN (:...${paramName})`, {
-            [paramName]: filter.value,
-          });
-          break;
-        case 'between':
-          queryBuilder.andWhere(
-            `entity.${filter.field} BETWEEN :${paramName}Start AND :${paramName}End`,
-            {
-              [`${paramName}Start`]: filter.value[0],
-              [`${paramName}End`]: filter.value[1],
-            }
-          );
-          break;
-        case 'isNull':
-          queryBuilder.andWhere(`entity.${filter.field} IS NULL`);
-          break;
-        case 'isNotNull':
-          queryBuilder.andWhere(`entity.${filter.field} IS NOT NULL`);
-          break;
-      }
-    });
+  /**
+   * Sanitiza nombre de campo para prevenir SQL injection
+   */
+  protected sanitizeFieldName(field: string): string {
+    // Solo permite caracteres alfanuméricos y guiones bajos
+    if (!/^[a-zA-Z_][a-zA-Z0-9_]*$/.test(field)) {
+      return this.config.defaultSortField || 'created_at';
+    }
+    return field;
+  }
+
+  /**
+   * Construye un INSERT dinámico
+   */
+  protected buildInsertQuery(
+    data: Record<string, any>,
+    additionalFields: Record<string, any> = {}
+  ): { sql: string; params: any[] } {
+    const allData = { ...data, ...additionalFields };
+    const fields = Object.keys(allData);
+    const values = Object.values(allData);
+    const placeholders = fields.map((_, i) => `$${i + 1}`);
+
+    const sql = `
+      INSERT INTO ${this.fullTableName} (${fields.join(', ')})
+      VALUES (${placeholders.join(', ')})
+      RETURNING ${this.config.selectFields}
+    `;
+
+    return { sql, params: values };
+  }
+
+  /**
+   * Construye un UPDATE dinámico
+   */
+  protected buildUpdateQuery(
+    id: string,
+    tenantId: string,
+    data: Record<string, any>
+  ): { sql: string; params: any[] } {
+    const fields = Object.keys(data).filter(k => data[k] !== undefined);
+    const setClauses = fields.map((f, i) => `${f} = $${i + 1}`);
+    const values = fields.map(f => data[f]);
+
+    // Agregar updated_at automáticamente
+    setClauses.push(`updated_at = CURRENT_TIMESTAMP`);
+
+    const paramIndex = fields.length + 1;
+
+    const sql = `
+      UPDATE ${this.fullTableName}
+      SET ${setClauses.join(', ')}
+      WHERE id = $${paramIndex} AND tenant_id = $${paramIndex + 1}
+      RETURNING ${this.config.selectFields}
+    `;
+
+    return { sql, params: [...values, id, tenantId] };
+  }
+
+  /**
+   * Redondea a N decimales
+   */
+  protected roundToDecimals(value: number, decimals: number = 2): number {
+    const factor = Math.pow(10, decimals);
+    return Math.round(value * factor) / factor;
   }
 }
+
+export default BaseService;