例1:在块定义部分声明了一个与错误”ORA-01401:inserted value too large for column”对应的用户自定义异常c_TooLarge。当在块的可执行部分向表中插入的列值超出指定的列长度时,则产生e_TooLarge异常 DECLARE v_Code %TYPE; e_TooLarge EXCEPTION; PRAGMAEXCEPTION_INIT(e_TooLarge,-1401); 1. 2. 3. 4....
lcm.large_subnational_region_name=lcmyv.large_subnational_region_name AND lcm.small_subnational_region_name=lcmyv.small_subnational_region_name AND lcm.year_value=lcmyv.max_year_value GROUP BY lcm.country_name, lcm.large_subnational_region_name, lcm.small_subnational_region_name, lcm.year_value ...
二进制字符串是一个字节数值的序列。SQL标准定义了一种不同的二进制字符串类型,叫做BLOB或者BINARY LARGE OBJECT,其输入格式和bytea不同,但是提供的函数和操作符大多一样。bytea类型数据的具体含义由应用程序自己决定,数据库也提供了和普通文本字符串的处理方式类似的方法来对bytea类型数据进行输入和输出。 可以使用...
CREATETABLEtest1 (acharacter(4));INSERTINTOtest1VALUES('ok');SELECTa,char_length(a)FROMtest1; CREATETABLEtest2 (bvarchar(5));INSERTINTOtest2VALUES('ok');INSERTINTOtest2VALUES('good ');INSERTINTOtest2VALUES('too long'); INSERTINTOtest2VALUES('too long'::varchar(5));SELECTb,char_length(b)F...
ERROR: VALUE too long FOR TYPE CHARACTER VARYING(9) 改变表或者列 当你需要改变一个域的定义时,你可以使用ALTER这一 SQL 关键字。例如,如果你想改变wordlist域中最多只能有 9 个字符的限制,你可以重新设置这个数据类型。 exampledb=> ALTER TABLE my_sample_table ...
postgres=# INSERT INTO test2 VALUES ('too long'); ERROR: value too long for type character varying(5) INSERT INTO test2 VALUES ('too long'::varchar(5)); -- explicit truncation SELECT b, char_length(b) FROM test2; b | char_length ...
Not having enough partitions may mean that indexes remain too large and that data locality remains poor which could result in low cache hit ratios. However, dividing the table into too many partitions can also cause issues. Too many partitions can mean longer query planning times and higher ...
…… if (*endptr != '\0' || errno == ERANGE) { /* integer too large (or contains decimal pt), treat it as a float */ return FCONST; } …… return ICONST; “1.x”这个符号既不能识别为数字,也不能识别为字符串,因此词法分析失败,直接报错: postgres=# INSERT INTO test_table VALU...
You can avoid this by setting wal_keep_segments to a value large enough to ensure that WAL segments are not recycled too early, or by configuring a replication slot for the standby. If you set up a WAL archive that’s accessible from the standby, these solutions are not required, since ...
Performance and scaling:PostgreSQL stands out for its strong performance and scalability, especially with complex queries and large datasets. While MySQL has traditionally excelled in simple, read-heavy operations, both systems have evolved to enhance their performance capabilities over time. Similarities ...