2、CONVERT() CONVERT (<data_ type>[ length ], <expression> [, style]) 1)data_type为SQL Server系统定义的数据类型,用户自定义的数据类型不能在此使用。 2)length用于指定数据的长度,缺省值为30。 3)把CHAR或VARCHAR类型转换为诸如INT或SAMLLINT这样的INTEGER类型、结果必须是带正号或负号的数值。 4)TEXT...
{publicstaticstringdataBaseFileName = AppDomain.CurrentDomain.BaseDirectory +"goods.db";publicstaticstringconnectionString =@"Data Source="+ dataBaseFileName +"; Pooling=true;FailIfMissing=false;";publicDBHelperSQLite() { }publicstaticvoidExistsDataBase() {if(!File.Exists(dataBaseFileName)) { SQLi...
static bool CreateTable(string db) { try { using (var con = new SQLiteConnection(db)) { con.Open(); using (var cmd = new SQLiteCommand(con)) { cmd.CommandText = "DROP TABLE IF EXISTS PrintDataInfo"; cmd.ExecuteNonQuery(); cmd.CommandText = @"CREATE TABLE PrintDataInfo(id INTEGER PR...
static bool CreateTable(string db) { try { using (var con = new SQLiteConnection(db)) { con.Open(); using (var cmd = new SQLiteCommand(con)) { cmd.CommandText = "DROP TABLE IF EXISTS PrintDataInfo"; cmd.ExecuteNonQuery(); cmd.CommandText = @"CREATE TABLE PrintDataInfo(id INTEGER PR...
--插入--注意:Integer允许自动增长(不要被Identity 忽悠)insertintoUserInfo(UserId,UserNames,UserPasss,RegDate)values(1001,'admin','admin','2021-01-21')insertintoUserInfo(UserId,UserNames,UserPasss,RegDate)values(1002,'sanha','sanha', datetime('now','localtime'))--查询select*fromUserInfo--Li...
Dateproperties can be mapped to either the 'TEXT' or to the 'INTEGER' storage class (defaults to 'INTEGER') and their values will be stored as UTC. Using 'INTEGER' converts to Unix-Time, so fractions of seconds are lost. This can be changed by using the field option 'dateInMilliSecond...
//Insertable:表示一个可插入的对象,有方法ContentValues convert(),将Entitiy转换为ContentValues public class FooEntity implements Queryable, Insertable { /** * 数据库自增id */ private int id; /** * entitiy id */ private String fooId;
INTEGER值是一个带符号的整数，根据值的大小存储在1、2、3、4、6或8字节中。REAL浮点数字，存储为8...
The table that the new column will be added to. The table name will be properly quoted by the method. $column string The name of the new column. The name will be properly quoted by the method. $type string The column type. The getColumnType() method will be invoked to convert abstrac...
{ connection.Open();stringsql ="SELECT * FROM users WHERE id = @id";using(varcommand =newSQLiteCommand(sql, connection)) {command.Parameters.AddWithValue("@id", id);using(SQLiteDataReader reader = command.ExecuteReader()) {if(reader.Read()) {returnnewUser {Id = Convert.ToInt32(reader[...