/// <summary>
/// 修改列。
/// </summary>
/// <param name="command">当前命令。</param>
/// <param name="builder">SQL语句构建实例。</param>
protected override void Generate(
AlterColumnCommand command,
IndentedStringBuilder builder)
{
Check.NotNull(command, nameof(command));
Check.NotNull(builder, nameof(builder));
DropDefaultConstraint(command.Schema, command.Table, command.Name, builder);
builder
.Append("ALTER TABLE ")
.Append(Sql.DelimitIdentifier(Prefix(command.Table), command.Schema))
.Append(" ALTER COLUMN ");
ColumnDefinition(
command.Schema,
command.Table,
command.Name,
command.ClrType,
command.ColumnType,
command.IsNullable,
/*identity:*/ false,
/*defaultValue:*/ null,
/*defaultValueSql:*/ null,
command.ComputedColumnSql,
command,
builder);
if (command.DefaultValue != null || command.DefaultValueSql != null)
{
builder
.AppendLine(";")
.Append("ALTER TABLE ")
.Append(Sql.DelimitIdentifier(Prefix(command.Table), command.Schema))
.Append(" ADD");
DefaultValue(command.DefaultValue, command.DefaultValueSql, builder);
builder
.Append(" FOR ")
.Append(Sql.DelimitIdentifier(command.Name));
}
}
/// <summary> /// 修改列。 /// </summary> /// <param name="command">当前命令。</param> /// <param name="builder">SQL语句构建实例。</param> protected abstract void Generate(AlterColumnCommand command, IndentedStringBuilder builder);