推荐一个 MYSQL 的命令行的客户端 MYCLI
MYCLI 是一个 MySQL 命令行客户端工具 , 可以实现自动补全(auto-completion)和语法高亮,平时测试环境维护一些数据还是蛮方便的。
https://github.com/dbcli/mycli ; 对应 postgres 也有相应的 pgcli https://github.com/dbcli/pgcli 。
#记录 MYSQL 的慢查询
默认 /etc/my.cnf mysql
在[mysqld]下加入
log-error=/usr/local/mysql/log/error.log #错误日志
log=/usr/local/mysql/log/mysql.log #查询日志
log-slow-queries= /usr/local/mysql/log/slowquery.log #慢查询日志什么是慢查询?
执行特别慢的sql会查到这个日志文件里。至于什么叫比较慢,由你自己来定义。譬如你认为是1秒就算慢了,那么要加入
log-slow-queries = /usr/local/mysql/var/slowquery.log #这个是上面的
long_query_time = 1 #一秒,代表你认为1秒就算慢了,当然你可以改成比1小的数字log-queries-not-using-indexes #如果执行的SQL语句没有使用索引,则mysql数据库同样会将这条SQL语句记录到慢查询日志文件中
Java, JDBC and MySQL Types
Table 5.2 MySQL Types to Java Types for ResultSet.getObject()
MySQL Type Name | Return value of GetColumnClassName | Returned as Java Class |
---|---|---|
BIT(1) (new in MySQL-5.0) |
BIT |
java.lang.Boolean |
BIT( > 1) (new in MySQL-5.0) |
BIT |
byte[] |
TINYINT |
TINYINT |
java.lang.Boolean if the configuration property tinyInt1isBit is set totrue (the default) and the storage size is 1, or java.lang.Integer if not. |
BOOL , BOOLEAN |
TINYINT |
See TINYINT , above as these are aliases for TINYINT(1) , currently. |
SMALLINT[(M)] [UNSIGNED] |
SMALLINT [UNSIGNED] |
java.lang.Integer (regardless of whether it is UNSIGNED or not) |
MEDIUMINT[(M)] [UNSIGNED] |
MEDIUMINT [UNSIGNED] |
java.lang.Integer (regardless of whether it is UNSIGNED or not) |
INT,INTEGER[(M)] [UNSIGNED] |
INTEGER [UNSIGNED] |
java.lang.Integer , if UNSIGNED java.lang.Long |
BIGINT[(M)] [UNSIGNED] |
BIGINT [UNSIGNED] |
java.lang.Long , if UNSIGNED java.math.BigInteger |
FLOAT[(M,D)] |
FLOAT |
java.lang.Float |
DOUBLE[(M,B)] |
DOUBLE |
java.lang.Double |
DECIMAL[(M[,D])] |
DECIMAL |
java.math.BigDecimal |
DATE |
DATE |
java.sql.Date |
DATETIME |
DATETIME |
java.sql.Timestamp |
TIMESTAMP[(M)] |
TIMESTAMP |
java.sql.Timestamp |
TIME |
TIME |
java.sql.Time |
YEAR[(2|4)] |
YEAR |
If yearIsDateType configuration property is set to false , then the returned object type is java.sql.Short . If set to true (the default), then the returned object is of type java.sql.Date with the date set to January 1st, at midnight. |
CHAR(M) |
CHAR |
java.lang.String (unless the character set for the column is BINARY , thenbyte[] is returned. |
VARCHAR(M) [BINARY] |
VARCHAR |
java.lang.String (unless the character set for the column is BINARY , thenbyte[] is returned. |
BINARY(M) |
BINARY |
byte[] |
VARBINARY(M) |
VARBINARY |
byte[] |
TINYBLOB |
TINYBLOB |
byte[] |
TINYTEXT |
VARCHAR |
java.lang.String |
BLOB |
BLOB |
byte[] |
TEXT |
VARCHAR |
java.lang.String |
MEDIUMBLOB |
MEDIUMBLOB |
byte[] |
MEDIUMTEXT |
VARCHAR |
java.lang.String |
LONGBLOB |
LONGBLOB |
byte[] |
LONGTEXT |
VARCHAR |
java.lang.String |
ENUM('value1','value2',...) |
CHAR |
java.lang.String |
SET('value1','value2',...) |
CHAR |
java.lang.String |
https://dev.mysql.com/doc/connector-j/5.1/en/connector-j-reference-type-conversions.html
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