swift SQLite自封装

1.数据库封装类MySQLiteManager

import Foundation
import SQLite3

//数据库封装类
class MySQLiteManager {
    private var db: OpaquePointer!
    
    //重写构造函数
    init(dbPath: String) {
        let isSuccess = openDB(dbPath: dbPath)
        if isSuccess {
            print("打开数据库成功")
        }else {
            print("打开数据库失败")
        }
    }
    
    //打开数据库
    func openDB(dbPath: String) -> Bool {
        let result = sqlite3_open(dbPath, &db)
        if result != SQLITE_OK { return false }
        return true
    }
    
    //关闭数据库
    func closeDB() {
        sqlite3_close(db)
    }
    
    deinit {
        sqlite3_close(db)
    }
}

extension MySQLiteManager {
    func createTable(sql: String) -> Bool {
        guard sql.contains("create") else { return false }
        return execSQL(sql: sql)
    }
    
    func dropTable(sql: String) -> Bool {
        guard sql.contains("drop") else { return false }
        return execSQL(sql: sql)
    }
}

extension MySQLiteManager {
    //MARK: - 插入
    func insert(sql: String) -> Bool {
        guard sql.contains("insert") else { return false }
        return execSQL(sql: sql)
    }
    //MARK: - 删除
    func delete(sql: String) -> Bool {
        guard sql.contains("delete") else { return false }
        return execSQL(sql: sql)
    }
    //MARK: - 修改
    func update(sql: String) -> Bool {
        guard sql.contains("update") else { return false }
        return execSQL(sql: sql)
    }
    func execSQL(sql: String) -> Bool {
        var errMsg: UnsafeMutablePointer? = nil
        let cSql = sql.cString(using: String.Encoding.utf8)!
        
        if sqlite3_exec(db, cSql, nil, nil, &errMsg) == SQLITE_OK {
            return true
        }
        let msg = String.init(cString: errMsg!)
        print(msg)
        
        return false
    }
    //MARK: - 查询
    func query(sql: String) -> [[String: Any]]? {
        guard sql.contains("select") else {
            print("sql语句有误")
            return nil
        }
        
        let cSql = sql.cString(using: String.Encoding.utf8)!
        var statement: OpaquePointer? = nil
        
        if sqlite3_prepare_v2(db, cSql, -1, &statement, nil) != SQLITE_OK {
            sqlite3_finalize(statement)
            
            print("执行\(sql)错误\n")
            let errmsg = sqlite3_errmsg(db)
            if errmsg != nil {
                print(errmsg!)
            }
            
            return nil
        }
        
        var rows = [[String: Any]]()
        
        while sqlite3_step(statement) == SQLITE_ROW {
            rows.append(record(statement: statement!))
        }
        
        sqlite3_finalize(statement)
        
        return rows
    }
    
    private func record(statement: OpaquePointer) -> [String: Any] {
        var row = [String: Any]()
        
        for col in 0 ..< sqlite3_column_count(statement) {
            let cName = sqlite3_column_name(statement, col)
            let name = String(cString: cName!, encoding: String.Encoding.utf8)
            
            var value: Any?
            
            switch (sqlite3_column_type(statement, col))
            {
            case SQLITE_FLOAT:
                value = sqlite3_column_double(statement, col) as Any
            case SQLITE_INTEGER:
                value = Int(sqlite3_column_int(statement, col)) as Any
            case SQLITE_TEXT:
                let cText = sqlite3_column_text(statement, col)
                value = String.init(cString: cText!) as Any
            case SQLITE_NULL:
                value = nil
            default:
                print("")
            }
            row[name!] = value
        }
        
        return row
    }
    
    //存储Blob数据 Blob（Binary Large Object）表示二进制类型的大对象。在数据库管理系统中，将二进制数据存储为一个单一个体的集合。
    func execSaveBlob(sql: String, blob: NSData) {
        let csql = sql.cString(using: .utf8)!
        var statement:OpaquePointer? = nil
        
        if sqlite3_prepare_v2(db, csql, -1, &statement, nil) != SQLITE_OK {
            sqlite3_finalize(statement)
            print("Prepare error:\(sql)")
            return
        }
        
        let paramsCnt = sqlite3_bind_parameter_count(statement)
        if paramsCnt != 1 {
            print("need only 1 parameter:\(sql)")
            sqlite3_finalize(statement)
            return
        }
        
        if sqlite3_bind_blob(statement, 1, blob.bytes, Int32(blob.length), nil) != SQLITE_OK {
            print("bind blob error:\(sql)")
            sqlite3_finalize(statement)
            return
        }
        
        let rslt = sqlite3_step(statement)
        if rslt != SQLITE_OK && rslt != SQLITE_DONE {
            print("extue blob error:\(sql)")
            sqlite3_finalize(statement)
            return
        }
        
        sqlite3_finalize(statement)
        return
        
    }
    
    //读取Blob数据
    func execLoadBlob(sql:String) -> Data? {
        let csql =  sql.cString(using: String.Encoding.utf8)!
        var statement:OpaquePointer? = nil
        
        if sqlite3_prepare_v2(db, csql, -1, &statement, nil) != SQLITE_OK {
            sqlite3_finalize(statement)
            print("执行\(sql)错误\n")
            if let errmsg = sqlite3_errmsg(db) {
                print(errmsg)
            }
            return nil
        }
        
        while sqlite3_step(statement) == SQLITE_ROW {
            if let dataBlob = sqlite3_column_blob(statement, 0) {
                let dataBlobLength = sqlite3_column_bytes(statement, 0)
                let data = Data(bytes: dataBlob, count: Int(dataBlobLength))
                sqlite3_finalize(statement)
                return data
            }
        }
        
        sqlite3_finalize(statement)
        return nil
    }
    
}

//MARK: - sql语句
/**
 1.DDL
 1.创建表

  create table if not exists t_student(id integer auto_increment primary key ,name
  varchar(3) , age int);
 删除表
 drop table if exists t_student;
 修改表结构
 alter table t_student add address varchar(4);
 alter table t_student modify address varchar(6) not null;
 tip：
 简单约束：
 name varchar(3) not null
 age int default 66
 主键约束：
 id integer auto_increment primary key

 2. DML
 1.插入数据

 insert into t_student(name,age,address) values ('xiaoM',12,'guangzhou');
 2.修改数据

 update t_student set name='xiaoHuang' where id=1;
 3.删除数据

 delete from t_student where id= 1 ;
 tip：
 条件约束
 delete from t_student where id is 1 or name = 'xiaoM';

 3. DQL
 查询语句
 1.查询所有字段信息

 select * from t_student;
 2.查询部分字段信息

 select name,age from t_student;
 3.查询符合条件下的部分字段信息

 select name,age from t_student where id=2;
 4.查询数据个数

 select count(*) from t_student;
 5.查询age不为空值的个数

 select count(age) from t_student;
 6.查询age平均值

 select avg(age) from t_student;
 7.查询age总和

 select sum(age) from t_student;
 8.查询age最大值

 select max(age) from t_student;
 9.查询age最小值

 select min(age) from t_student;
 10.查询按分数升序，按年龄降序

 select *from t_student order by score asc, age desc;
 */

2.针对表test写的类TestTableManager

import Foundation

class TestTableManager {
    private var sqliteManager: MySQLiteManager!
    static let shared = TestTableManager()
    
    init() {
        let dbPath = NSHomeDirectory() + "/Documents/testDB.sqlite"
        sqliteManager = MySQLiteManager(dbPath: dbPath)
        createTable()
    }
    
    private func createTable() {
        let sql = "create table if not exists test (id integer auto_increment primary key ,name char(50) not null default '');"
        if sqliteManager.createTable(sql: sql) {
            print("表创建成功")
        }else {
            print("表创建失败")
        }
    }
    
    func dropTable() {
        let sql = "drop table if exists test;"
        if sqliteManager.dropTable(sql: sql) {
            print("表删除成功")
        }else {
            print("表删除失败")
        }
    }
    
    func insert(name: String) {
        let sql = "insert into  test(name) values ('\(name)');"
        let isSuccess = sqliteManager.insert(sql: sql)
        if isSuccess {
            print("插入成功")
        }else {
            print("插入失败")
        }
    }
    
    func quary() {
        let sql = "select * from test;"
        let data = sqliteManager.query(sql: sql)
        print(data!)
    }
}

3.测试代码

import UIKit

class ViewController: UIViewController {
    
    override func viewDidLoad() {
        super.viewDidLoad()

        //MARK: - sqlite自封装
        TestTableManager.shared.insert(name: "aaaaa")
        TestTableManager.shared.insert(name: "bbbbb")
        TestTableManager.shared.quary()
        TestTableManager.shared.dropTable()
    }
    
    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)
        
    }
}