搜尋

kangear注:此文描述了u-boot中的分区 开启调试 修改wyh2440.h /* *debug enable */ #define DEBUG #define CONFIG_NAND_DEBUG 修改s3c2440_nand.c #if !defined(CONFIG_NAND_DEBUG) #undef debug #define debug(fmt,args...) #endif #define S3C2440_ADDR_N

kangear注:此文描述了u-boot中的分区

开启调试

修改wyh2440.h
/*
 *debug enable
 */
#define DEBUG
#define CONFIG_NAND_DEBUG

修改s3c2440_nand.c

+#if !defined(CONFIG_NAND_DEBUG)
+#undef debug
+#define debug(fmt,args...)
+#endif

+#define S3C2440_ADDR_NALE 0x08
+#define S3C2440_ADDR_NCLE 0x0c

修改 s3c2440_hwcontrol 函数
static void s3c2440_hwcontrol(struct mtd_info *mtd, int cmd, unsigned int ctrl)
{
 struct nand_chip *chip = mtd->priv;
 struct s3c2440_nand *nand = s3c2440_get_base_nand();

 debug("hwcontrol(): 0x%02x 0x%02x\n", cmd, ctrl);

 if (ctrl & NAND_CTRL_CHANGE) {
  ulong IO_ADDR_W = (ulong)nand;

  if (!(ctrl & NAND_CLE))
   IO_ADDR_W |= S3C2440_ADDR_NCLE;
  if (!(ctrl & NAND_ALE))
   IO_ADDR_W |= S3C2440_ADDR_NALE;
                if(cmd == NAND_CMD_NONE)
                        IO_ADDR_W = (ulong)&nand->nfdata;

  chip->IO_ADDR_W = (void *)IO_ADDR_W;
/*
  if (ctrl & NAND_NCE)
   writel(readl(&nand->nfconf) & ~S3C2440_NFCONF_nFCE,
          &nand->nfconf);
  else
   writel(readl(&nand->nfconf) | S3C2440_NFCONF_nFCE,
          &nand->nfconf);
*/
 }

 if (cmd != NAND_CMD_NONE)
  writeb(cmd, chip->IO_ADDR_W);
}


没完没了的hwcontrol() dev_ready打印信息
还是取消nand 的debug信息吧
/*#define CONFIG_NAND_DEBUG*/

make download go

U-Boot 2012.04.01 (Jul 03 2012 - 11:51:29)

U-Boot code: 30000000 -> 3006C274  BSS: -> 300AF944
CPUID: 32440001
FCLK:      400 MHz
HCLK:      100 MHz
PCLK:       50 MHz
monitor len: 000AF944
ramsize: 04000000
TLB table at: 33ff0000
Top of RAM usable for U-Boot at: 33ff0000
Reserving 702k for U-Boot at: 33f40000
Reserving 4096k for malloc() at: 33b40000
Reserving 36 Bytes for Board Info at: 33b3ffdc
Reserving 120 Bytes for Global Data at: 33b3ff64
New Stack Pointer is: 33b3ff58
RAM Configuration:
Bank #0: 30000000 64 MiB
relocation Offset is: 03f40000
WARNING: Caches not enabled
monitor flash len: 00074ADC
dram_bank_mmu_setup: bank: 0
Now running in RAM - U-Boot at: 33f40000
NAND:  256 MiB
*** Warning - bad CRC, using default environment

Destroy Hash Table: 33fadd70 table = (null)
Create Hash Table: N=75
INSERT: table 33fadd70, filled 1/79 rv 33b42a78 ==> name="bootdelay" value="5"
INSERT: table 33fadd70, filled 2/79 rv 33b429b8 ==> name="baudrate" value="115200"
INSERT: table 33fadd70, filled 3/79 rv 33b42988 ==> name="ipaddr" value="10.0.0.110"
INSERT: table 33fadd70, filled 4/79 rv 33b42a90 ==> name="serverip" value="10.0.0.1"
INSERT: table 33fadd70, filled 5/79 rv 33b42c1c ==> name="netmask" value="255.255.255.0"
INSERT: free(data = 33b42900)
INSERT: done
In:    serial
Out:   serial
Err:   serial
Net:   CS8900-0
### main_loop entered: bootdelay=5

### main_loop: bootcmd=""
SMDK2410 #

SMDK2410 # nand info           

Device 0: nand0, sector size 128 KiB
  Page size      2048 b
  OOB size         64 b
  Erase size   131072 b
  
SMDK2410 # nand erase 0x640000 0x20000
测试nand  写入输入到offset 0x640000 size 为0x20000

NAND erase: device 0 offset 0x640000, size 0x20000
Erasing at 0x640000 -- 100% complete.
OK
SMDK2410 #

SMDK2410 # nand write 0x30000000 0x640000 0x20000

NAND write: device 0 offset 0x640000, size 0x20000
 131072 bytes written: OK
SMDK2410 # md 30000000
30000000: ea000013 e59ff014 e59ff014 e59ff014    ................
30000010: e59ff014 e59ff014 e59ff014 e59ff014    ................
30000020: 30000200 30000260 300002c0 30000320    ...0`..0...0 ..0
30000030: 30000380 300003e0 30000440 deadbeef    ...0...0@..0....
30000040: 30000000 0006c274 000af944 00074adc    ...0t...D....J..
30000050: 0badc0de e10f0000 e3c0001f e38000d3    ................
30000060: e129f000 e3a00453 e3a01000 e5801000    ..).S...........
30000070: e3e01000 e59f040c e5801000 e59f1408    ................
30000080: e59f0408 e5801000 e59f0404 e3a01005    ................
30000090: e5801000 ee111f10 e3811103 ee011f10    ................
300000a0: eb000044 e59fd3ec e3cdd007 e3a00000    D...............
300000b0: eb000825 e1a04000 e1a05001 e1a06002    %....@...P...`..
300000c0: e1a0d004 e24f00cc e1500006 0a000022    ......O...P."...
300000d0: e1a01006 e51f3098 e0802003 e8b00600    .....0... ......
300000e0: e8a10600 e1500002 3afffffb e51f00b4    ......P....:....
300000f0: e0469000 e59fa0b8 e08aa000 e59f20a8    ..F.......... ..
SMDK2410 # nand dump 640000
Page 00640000 dump:
        13 00 00 ea 14 f0 9f e5  14 f0 9f e5 14 f0 9f e5
        14 f0 9f e5 14 f0 9f e5  14 f0 9f e5 14 f0 9f e5
        00 02 00 30 60 02 00 30  c0 02 00 30 20 03 00 30
        80 03 00 30 e0 03 00 30  40 04 00 30 ef be ad de
        00 00 00 30 74 c2 06 00  44 f9 0a 00 dc 4a 07 00
        de c0 ad 0b 00 00 0f e1  1f 00 c0 e3 d3 00 80 e3
        00 f0 29 e1 53 04 a0 e3  00 10 a0 e3 00 10 80 e5
        00 10 e0 e3 0c 04 9f e5  00 10 80 e5 08 14 9f e5
        08 04 9f e5 00 10 80 e5  04 04 9f e5 05 10 a0 e3
        00 10 80 e5 10 1f 11 ee  03 11 81 e3 10 1f 01 ee
        44 00 00 eb ec d3 9f e5  07 d0 cd e3 00 00 a0 e3
        25 08 00 eb 00 40 a0 e1  01 50 a0 e1 02 60 a0 e1
        04 d0 a0 e1 cc 00 4f e2  06 00 50 e1 22 00 00 0a
        06 10 a0 e1 98 30 1f e5  03 20 80 e0 00 06 b0 e8
        00 06 a1 e8 02 00 50 e1  fb ff ff 3a b4 00 1f e5
        00 90 46 e0 b8 a0 9f e5  00 a0 8a e0 a8 20 9f e5
        00 20 82 e0 a4 30 9f e5  00 30 83 e0 00 00 92 e5
        09 00 80 e0 04 10 92 e5  ff 70 01 e2 17 00 57 e3
        07 00 00 0a 02 00 57 e3  00 00 00 0a 06 00 00 ea
        21 12 a0 e1 01 10 8a e0  04 10 91 e5 09 10 81 e0
        01 00 00 ea 00 10 90 e5  09 10 81 e0 00 10 80 e5
        08 20 82 e2 03 00 52 e1  eb ff ff 3a 20 01 1f e5
        20 11 1f e5 06 40 a0 e1  04 00 80 e0 04 10 81 e0
        00 20 a0 e3 00 20 80 e5  04 00 80 e2 01 00 50 e1
        fb ff ff 1a 7b 07 00 eb  7b 07 00 eb 14 00 9f e5
        66 1f 4f e2 01 e0 80 e0  09 e0 8e e0 05 00 a0 e1
        06 10 a0 e1 0e f0 a0 e1  4c 20 00 00 74 c2 06 00
        0c 4a 07 00 0c 4a 07 00  00 00 a0 e3 17 0f 07 ee
        17 0f 08 ee 10 0f 11 ee  23 0c c0 e3 87 00 c0 e3
        02 00 80 e3 01 0a 80 e3  10 0f 01 ee 0e c0 a0 e1
        0c e0 a0 e1 0e f0 a0 e1  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        b8 d1 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  e0 21 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 71 09 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        18 d2 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  40 22 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 50 09 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        78 d2 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  a0 22 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 2f 09 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        d8 d2 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  00 23 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 0e 09 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        38 d3 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  60 23 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 ed 08 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        98 d3 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  c0 23 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 c3 08 00 eb  00 00 a0 e1 00 00 a0 e1
        00 00 a0 e1 00 00 a0 e1  00 00 a0 e1 00 00 a0 e1
        f8 d3 1f e5 00 e0 8d e5  00 e0 4f e1 04 e0 8d e5
        13 d0 a0 e3 0d f0 69 e1  0f e0 a0 e1 0e f0 b0 e1
        48 d0 4d e2 ff 1f 8d e8  20 24 1f e5 0c 00 92 e8
        48 00 8d e2 34 50 8d e2  0e 10 a0 e1 0f 00 85 e8
        0d 00 a0 e1 b4 08 00 eb  08 00 00 4a ff 7f 00 00
        1c 00 00 4a 14 00 00 4c  80 ff ff 33 00 00 a0 e1
        10 40 2d e9 4d 08 00 eb  20 09 00 eb 1d 09 00 eb
        00 30 a0 e3 17 3f 07 ee  00 00 a0 e3 10 80 bd e8
        30 40 2d e9 80 30 9f e5  24 d0 4d e2 00 10 93 e5
        78 00 9f e5 d8 37 00 eb  47 00 00 eb 00 10 a0 e1
        0d 00 a0 e1 76 28 01 eb  64 50 9f e5 00 20 a0 e1
        46 10 a0 e3 05 00 a0 e1  cf 37 00 eb 40 00 00 eb
        00 10 a0 e1 0d 00 a0 e1  6d 28 01 eb 48 10 a0 e3
        00 20 a0 e1 05 00 a0 e1  c7 37 00 eb 5f 00 00 eb
        00 10 a0 e1 0d 00 a0 e1  65 28 01 eb 50 10 a0 e3
        00 20 a0 e1 05 00 a0 e1  bf 37 00 eb 0d 40 a0 e1
        00 00 a0 e3 24 d0 8d e2  30 80 bd e8 b0 00 00 56
        b5 99 05 30 c2 99 05 30  00 00 50 e3 10 40 2d e9
        02 00 00 1a 7c 30 9f e5  00 30 93 e5 03 00 00 ea
        01 00 50 e3 0d 00 00 1a  6c 30 9f e5 00 30 93 e5
        03 20 a0 e1 3f 3e 03 e2  ff 1a 02 e2 23 32 a0 e1
        21 16 a0 e1 02 30 83 e2  03 20 02 e2 00 00 50 e3
        13 22 a0 e1 08 40 81 e2  07 00 00 1a 00 00 00 ea
        a1 06 00 eb 02 10 a0 e1  30 00 9f e5 b9 54 01 eb
        84 40 a0 e1 90 04 03 e0  04 00 00 ea 1c 30 9f e5
        02 10 a0 e1 93 04 00 e0  b2 54 01 eb 00 30 a0 e1
        03 00 a0 e1 10 80 bd e8  04 00 00 4c 08 00 00 4c
        00 1b b7 00 01 00 a0 e3  d6 ff ff ea 00 00 a0 e3
        d4 ff ff ea 8c 30 9f e5  10 40 2d e9 00 30 93 e5
        06 40 03 e2 04 00 54 e3  08 00 00 0a 06 00 54 e3
        10 00 00 0a 02 00 54 e3  01 00 00 0a 10 40 bd e8
        f1 ff ff ea f0 ff ff eb  a0 00 a0 e1 10 80 bd e8
        54 30 9f e5 00 30 93 e5  02 0c 13 e3 02 00 00 0a
        e9 ff ff eb a0 01 a0 e1  10 80 bd e8 e6 ff ff eb
        20 01 a0 e1 10 80 bd e8  2c 30 9f e5 00 30 93 e5
        01 0c 13 e3 03 00 00 0a  df ff ff eb 04 10 a0 e1
        88 54 01 eb 10 80 bd e8  db ff ff eb 03 10 a0 e3
        84 54 01 eb 10 80 bd e8  14 00 00 4c 18 00 00 4c
        20 30 9f e5 10 40 2d e9  00 30 93 e5 01 00 13 e3
        02 00 00 0a d2 ff ff eb  a0 00 a0 e1 10 80 bd e8
        10 40 bd e8 ce ff ff ea  14 00 00 4c 5c 30 9f e5
        00 30 93 e5 03 c8 a0 e1  30 30 98 e5 2c c8 a0 e1
        0c 00 53 e1 08 00 a0 e1  05 00 00 3a 20 20 98 e5
        30 30 98 e5 02 30 83 e0  03 30 6c e0 20 30 88 e5
        06 00 00 ea 20 30 98 e5  30 20 98 e5 24 10 98 e5
        03 20 82 e0 01 20 82 e0  02 20 6c e0 20 20 88 e5
        30 c0 80 e5 00 10 a0 e3  20 00 90 e5 0e f0 a0 e1
        40 00 00 51 fa 0f 50 e3  10 40 2d e9 00 10 a0 e1
        07 00 00 3a fa 1f a0 e3  56 54 01 eb 24 20 98 e5
        64 30 a0 e3 92 03 03 e0  fa 1f a0 e3 93 00 00 e0
        04 00 00 ea 24 20 98 e5  64 30 a0 e3 92 03 03 e0
        91 03 00 e0 20 10 9f e5  4a 54 01 eb 00 40 a0 e1
        d1 ff ff eb 00 40 84 e0  cf ff ff eb 04 00 60 e0
        00 00 50 e3 fb ff ff aa  10 80 bd e8 40 42 0f 00
        10 40 2d e9 c8 ff ff eb  fa 1f a0 e3 00 40 a0 e1
        1c 00 98 e5 3b 54 01 eb  00 10 a0 e1 04 00 a0 e1
        38 54 01 eb 10 80 bd e8  10 40 2d e9 00 40 a0 e1
        f2 ff ff eb 00 00 64 e0  10 80 bd e8 70 40 2d e9
        00 40 a0 e1 b8 ff ff eb  fa 1f a0 e3 00 50 a0 e1
        04 00 a0 e1 2b 54 01 eb  24 20 98 e5 64 30 a0 e3
OOB:
        ff ff ff ff ff ff ff ff
        ff ff ff ff ff ff ff ff
        ff ff ff ff ff ff ff ff
        ff ff ff ff ff ff ff ff
        ff ff ff ff ff ff ff ff
        59 99 5b aa a9 6b a9 a5
        9b fc c3 33 c3 30 33 3f
        c0 f3 65 95 57 cc 3f cf
Command failed, result=1SMDK2410 #

SMDK2410 # nand read 31000000 640000 20000

NAND read: device 0 offset 0x640000, size 0x20000
 131072 bytes read: OK
SMDK2410 # cmp 30000000 31000000 20000
word at 0x30020000 (0xe3a01030) != word at 0x31020000 (0xc5060008)
Total of 32768 words were the same
Command failed, result=1SMDK2410 #

正好0x20000个字的数据匹配

 

SMDK2410 # mtd

---mtdparts_init---
last_ids  : 
env_ids   :
last_parts: 
env_parts :

last_partition : 
env_partition  :
mtdids not defined, no default present

 

 

 

 

添加mtd分区

修改wyh2440.h
#define MTDIDS_DEFAULT          "nand0=nandflash0"

#define MTDPARTS_DEFAULT        "mtdparts=nandflash0:"                          \
                                "128k@0(spl),"/*offset 0x000000*/               \
                                "128k(env),"  /*offset 0x020000*/               \
                                "1m(logo),"   /*offset 0x040000*/               \
                                "1m(u-boot)," /*offset 0x140000*/               \
                                "4m(kernel)," /*offset 0x240000*/               \
                                "-(rootfs)"   /*offset 0x640000*/
#define CONFIG_EXTRA_ENV_SETTINGS       "mtdid=" MTDIDS_DEFAULT "\0"            \
                                        "mtdparts=" MTDPARTS_DEFAULT "\0"


make download go

 

 

 

 

SMDK2410 # mtd

---mtdparts_init---
last_ids  : 
env_ids   :
last_parts: 
env_parts : mtdparts=nandflash0:128k@0(spl),128k(env),1m(logo),1m(u-boot),4m(kernel),-(rootfs)

last_partition : 
env_partition  :
mtdids variable not defined, using default

---parse_mtdids---
mtdids = nand0=nandflash0

+ id nand0             268435456 bytes  nandflash0

---parse_mtdparts---
mtdparts = mtdparts=nandflash0:128k@0(spl),128k(env),1m(logo),1m(u-boot),4m(kernel),-(rootfs)

--- current_save ---
hdelete: DELETE key "partition"
=> partition NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
===device_parse===
--- id_find_by_mtd_id: 'nandflash0' (len = 10)
entry: 'nandflash0' (len = 10)
dev type = 2 (nand), dev num = 0, mtd-id = nandflash0
parsing partitions 128k@0(spl),128k(env),1m(logo),1m(u-boot),4m(kernel),-(rootfs)
+ partition: name spl                    size 0x00020000 offset 0x00000000 mask flags 0
+ partition: name env                    size 0x00020000 offset 0xffffffff mask flags 0
+ partition: name logo                   size 0x00100000 offset 0xffffffff mask flags 0
+ partition: name u-boot                 size 0x00100000 offset 0xffffffff mask flags 0
+ partition: name kernel                 size 0x00400000 offset 0xffffffff mask flags 0
'-': remaining size assigned
+ partition: name rootfs                 size 0xffffffff offset 0xffffffff mask flags 0

total partitions: 6
part_sort_add: list empty
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
--- index partitions ---
hdelete: DELETE key "mtddevnum"
hdelete: DELETE key "mtddevname"
=> mtddevnum NULL
=> mtddevname NULL
===

+ device: nand  0       nandflash0
--- current_save ---
=> partition nand0,0
--- index partitions ---

--- mtd_part_info: partition number 0 for device nand0 (nandflash0)
=> mtddevnum 0,
=> mtddevname spl
mtdparts_init: current_mtd_dev  = nand0, current_mtd_partnum = 0

---list_partitions---

device nand0 , # parts = 6
 #: name                size            offset          mask_flags
 0: spl                 0x00020000      0x00000000      0
 1: env                 0x00020000      0x00020000      0
 2: logo                0x00100000      0x00040000      0
 3: u-boot              0x00100000      0x00140000      0
 4: kernel              0x00400000      0x00240000      0
 5: rootfs              0x0f9c0000      0x00640000      0

--- mtd_part_info: partition number 0 for device nand0 (nandflash0)

active partition: nand0,0 - (spl) 0x00020000 @ 0x00000000

defaults:
mtdids  : nand0=nandflash0
mtdparts: mtdparts=nandflash0:128k@0(spl),128k(env),1m(logo),1m(u-boot),4m(kernel),-(rootfs)
SMDK2410 # 

http://blog.163.com/yihui_wang/blog/static/1862154902012638928107/

陳述
本文內容由網友自願投稿,版權歸原作者所有。本站不承擔相應的法律責任。如發現涉嫌抄襲或侵權的內容,請聯絡admin@php.cn
將用戶添加到MySQL:完整的教程將用戶添加到MySQL:完整的教程May 12, 2025 am 12:14 AM

掌握添加MySQL用戶的方法對於數據庫管理員和開發者至關重要,因為它確保數據庫的安全性和訪問控制。 1)使用CREATEUSER命令創建新用戶,2)通過GRANT命令分配權限,3)使用FLUSHPRIVILEGES確保權限生效,4)定期審計和清理用戶賬戶以維護性能和安全。

掌握mySQL字符串數據類型:varchar vs.文本與char掌握mySQL字符串數據類型:varchar vs.文本與charMay 12, 2025 am 12:12 AM

chosecharforfixed-lengthdata,varcharforvariable-lengthdata,andtextforlargetextfield.1)chariseffity forconsistent-lengthdatalikecodes.2)varcharsuitsvariable-lengthdatalikenames,ballancingflexibilitibility andperformance.3)

MySQL:字符串數據類型和索引:最佳實踐MySQL:字符串數據類型和索引:最佳實踐May 12, 2025 am 12:11 AM

在MySQL中處理字符串數據類型和索引的最佳實踐包括:1)選擇合適的字符串類型,如CHAR用於固定長度,VARCHAR用於可變長度,TEXT用於大文本;2)謹慎索引,避免過度索引,針對常用查詢創建索引;3)使用前綴索引和全文索引優化長字符串搜索;4)定期監控和優化索引,保持索引小巧高效。通過這些方法,可以在讀取和寫入性能之間取得平衡,提升數據庫效率。

mysql:如何遠程添加用戶mysql:如何遠程添加用戶May 12, 2025 am 12:10 AM

ToaddauserremotelytoMySQL,followthesesteps:1)ConnecttoMySQLasroot,2)Createanewuserwithremoteaccess,3)Grantnecessaryprivileges,and4)Flushprivileges.BecautiousofsecurityrisksbylimitingprivilegesandaccesstospecificIPs,ensuringstrongpasswords,andmonitori

MySQL字符串數據類型的最終指南:有效的數據存儲MySQL字符串數據類型的最終指南:有效的數據存儲May 12, 2025 am 12:05 AM

tostorestringsefliceflicyInmySql,ChooSetherightDataTypeBasedyOrneOrneEds:1)USEcharforFixed-LengthStstringStringStringSlikeCountryCodes.2)UseVarcharforvariable-lengtthslikenames.3)USETEXTCONTENT.3)

mysql blob vs.文本:為大對象選擇正確的數據類型mysql blob vs.文本:為大對象選擇正確的數據類型May 11, 2025 am 12:13 AM

選擇MySQL的BLOB和TEXT數據類型時,BLOB適合存儲二進制數據,TEXT適合存儲文本數據。 1)BLOB適用於圖片、音頻等二進制數據,2)TEXT適用於文章、評論等文本數據,選擇時需考慮數據性質和性能優化。

MySQL:我應該將root用戶用於產品嗎?MySQL:我應該將root用戶用於產品嗎?May 11, 2025 am 12:11 AM

No,youshouldnotusetherootuserinMySQLforyourproduct.Instead,createspecificuserswithlimitedprivilegestoenhancesecurityandperformance:1)Createanewuserwithastrongpassword,2)Grantonlynecessarypermissionstothisuser,3)Regularlyreviewandupdateuserpermissions

MySQL字符串數據類型說明了:選擇適合您數據的合適類型MySQL字符串數據類型說明了:選擇適合您數據的合適類型May 11, 2025 am 12:10 AM

mySqlStringDatatAtatPessHouldBechoseBasedondatActarActeristicsAndusecases:1)USEcharforFixed lengthStstringStringStringSlikeCountryCodes.2)usevarcharforvariable-lengtthslikeLikenames.3)usebarnionororvarinyorvarinyorvarybinarydatalgebenedaTalgeextocrabextrapon.4)

See all articles

熱AI工具

Undresser.AI Undress

Undresser.AI Undress

人工智慧驅動的應用程序,用於創建逼真的裸體照片

AI Clothes Remover

AI Clothes Remover

用於從照片中去除衣服的線上人工智慧工具。

Undress AI Tool

Undress AI Tool

免費脫衣圖片

Clothoff.io

Clothoff.io

AI脫衣器

Video Face Swap

Video Face Swap

使用我們完全免費的人工智慧換臉工具,輕鬆在任何影片中換臉!

熱門文章

熱工具

SAP NetWeaver Server Adapter for Eclipse

SAP NetWeaver Server Adapter for Eclipse

將Eclipse與SAP NetWeaver應用伺服器整合。

Dreamweaver Mac版

Dreamweaver Mac版

視覺化網頁開發工具

記事本++7.3.1

記事本++7.3.1

好用且免費的程式碼編輯器

mPDF

mPDF

mPDF是一個PHP庫,可以從UTF-8編碼的HTML產生PDF檔案。原作者Ian Back編寫mPDF以從他的網站上「即時」輸出PDF文件,並處理不同的語言。與原始腳本如HTML2FPDF相比,它的速度較慢,並且在使用Unicode字體時產生的檔案較大,但支援CSS樣式等,並進行了大量增強。支援幾乎所有語言,包括RTL(阿拉伯語和希伯來語)和CJK(中日韓)。支援嵌套的區塊級元素(如P、DIV),

ZendStudio 13.5.1 Mac

ZendStudio 13.5.1 Mac

強大的PHP整合開發環境