{"id":49,"date":"2011-09-27T06:47:46","date_gmt":"2011-09-27T06:47:46","guid":{"rendered":"http:\/\/sql.programisius.lt\/?page_id=49"},"modified":"2011-10-02T16:48:23","modified_gmt":"2011-10-02T16:48:23","slug":"4-lenteliu-kurimas","status":"publish","type":"page","link":"http:\/\/sql.programisius.lt\/?page_id=49","title":{"rendered":"4. Lenteli\u0173 k\u016brimas"},"content":{"rendered":"

Komanda CREATE TABLE yra skirta sukurti lentel\u0119. Lentel\u0117s k\u016brimo SQL \u0161ablonas yra toks:<\/p>\n

\u00a0CREATE TABLE lentel\u0117s_vardas(<\/span>
\n \u00a0stulpelio_vardas1 duomens_tipas,<\/span>
\n \u00a0stulpelio_vardas2 duomens_tipas,<\/span>
\n \u00a0stulpelio_vardas3 duomens_tipas );<\/span><\/p><\/blockquote>\n

Norint sukurti su papildomom taisykl\u0117m lentel\u0117s stulpelius, \u0161ablonas pakinta \u012f tok\u012f:<\/p>\n

\u00a0CREATE TABLE lentel\u0117s_vardas(<\/span>
\n \u00a0stulpelio_vardas1 duomens_tipas [taisykl\u0117],<\/span>
\n \u00a0stulpelio_vardas2 duomens_tipas [taisykl\u0117],<\/span>
\n \u00a0stulpelio_vardas3 duomens_tipas [taisykl\u0117] );<\/span><\/p>\n

[] \u2013 pasirenkamas<\/span><\/p><\/blockquote>\n

Stulpeli\u0173 galima sukurti tok\u012f skai\u010di\u0173, koks pageidaujamas. Stulpeli\u0173 vardai tur\u0117t\u0173 b\u016bti tik angli\u0161kos ab\u0117c\u0117l\u0117s raid\u017ei\u0173.<\/p>\n

Sukurkime lentel\u0119 darbuotojai, kuri atrodyt\u0173 taip:<\/p>\n\n\n\n\n\n
\n

vardas<\/strong><\/p>\n<\/td>\n

\n

pavarde<\/strong><\/p>\n<\/td>\n

\n

amzius<\/strong><\/p>\n<\/td>\n

\n

adresas <\/strong><\/p>\n<\/td>\n

\n

miestas<\/strong><\/p>\n<\/td>\n<\/tr>\n

<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n
<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

SQL komanda:<\/p>\n

\u00a0CREATE TABLE darbuotojai (<\/span>
\n vardas varchar(15),<\/span>
\n pavarde varchar(20),<\/span>
\n amzius number(3),<\/span>
\n adresas varchar(30),<\/span>
\n miestas varchar(20));<\/span><\/p><\/blockquote>\n

Sukurti lentel\u0119, reikia ra\u0161yti CREATE TABLE. Po to atidaromi skliausteliai ir nurodomas pirmas stulpelis. Po tarpelio nurodomas duomens tipas. Pad\u0117jus kablel\u012f nurodomas antras stulpelis. Taip kartojama iki paskutinio stulpelio, kuris jau u\u017esibaigia paprastu u\u017edarymo skliausteliu. Po vis\u0173 SQL komand\u0173 visada yra dedamas kabliata\u0161kis (;), tad ir \u0161i komanda baigiama juo.<\/p>\n

Lenteli\u0173 ir stulpeli\u0173 vardai visada privalo prasid\u0117ti raide, po kurios gali eiti kiti simboliai, tokie kaip skai\u010diai.<\/p>\n

Da\u017eniausiai naudojami duomens tipai:<\/p>\n

char(dydis)<\/span> \u2013 fiksuoto ilgio simbolin\u0117 eilut\u0117. Dydis nurodo kokio tiksliai ilgio visada yra eilut\u0117.<\/p>\n

varchar(dydis)<\/span> \u2013 kintamo ilgio simbolin\u0117 eilut\u0117. Dydis nurodo kokia ilgiausia tkstin\u0117 eilut\u0117 gali b\u016bti.<\/p>\n

integer<\/span>\u00a0–\u00a0 skai\u010dius, o nurodytas dydis apibr\u0117\u017eia kiek skaitmen\u0173 jis gali b\u016bti.<\/p>\n

date<\/span> –\u00a0 laiko vert\u0117s duomuo<\/p>\n

decimal(dydis, d)<\/span> \u2013 skai\u010dius, kurio skaitmen\u0173 skai\u010dius nurodytas parametru dydis, o d nurodo skaitmen\u0173 skai\u010di\u0173 po kablelio.<\/p>\n

Kuriant lenteles, stulpeliams galima nurodyti taisykles. Pavyzd\u017eiui \u201eUNIQUE\u201c nurodo, kad tame stulpelyje vis\u0173 eilu\u010di\u0173 domenai (\u012fra\u0161ai pagal stulpel\u012f) turi b\u016bti skirtingi. Kita populiari taisykl\u0117, kad stulpelis negali b\u016bti nulinis (NOT NULL), kas rei\u0161kia, kad stulpelis negal\u0117s b\u016bti nei tu\u0161\u010dias, nei \u201epirminis raktas\u201c (PRIMARY KEY). \u201ePirminis raktas\u201c apibr\u0117\u017eia eilut\u0117s unikal\u0173 vard\u0105, tad jis kartu taip pat turi visas UNIQUE savybes.<\/p>\n

Lenteles galima ir pa\u0161alinti. J\u0173 \u0161alinimas yra su komanda DROP apie kuri\u0105 bus v\u0117liau.<\/p>\n

\u00a0CREATE TABLE u\u017eduotis<\/strong><\/p>\n

J\u016bs tik k\u0105 \u012fk\u016br\u0117te savo versl\u0105. Dabar mums reikia susikurti lentel\u0119 apie \u012fdarbintus darbuotojus. Informacija apie darbuotoj\u0105 reikalinga yra vardas, pavard\u0117, pareigos, am\u017eius ir alga. SQL interpretatorius suteik\u0117 resursus ir lentelei i\u0161skyr\u0117 jums vard\u0105\u00a0 nurodyt\u0105 \u017eemiau.<\/p>\n

Kai tik j\u0105 pavyks sukursim, bus galima pereiti prie kitos u\u017eduoties, t.y. duomen\u0173 \u012fvedimo su INSERT. Beje, SQL interpretatorius duomenis laiko apie kelias dienas.<\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Komanda CREATE TABLE yra skirta sukurti lentel\u0119. Lentel\u0117s k\u016brimo SQL \u0161ablonas yra toks: \u00a0CREATE TABLE lentel\u0117s_vardas( \u00a0stulpelio_vardas1 duomens_tipas, \u00a0stulpelio_vardas2 duomens_tipas, \u00a0stulpelio_vardas3 duomens_tipas ); Norint sukurti su papildomom taisykl\u0117m lentel\u0117s stulpelius, \u0161ablonas pakinta \u012f tok\u012f: \u00a0CREATE TABLE lentel\u0117s_vardas( \u00a0stulpelio_vardas1 duomens_tipas [taisykl\u0117], \u00a0stulpelio_vardas2 duomens_tipas [taisykl\u0117], \u00a0stulpelio_vardas3 duomens_tipas [taisykl\u0117] ); [] \u2013 pasirenkamas Stulpeli\u0173 galima sukurti tok\u012f skai\u010di\u0173, […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":2,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-49","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/pages\/49","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=49"}],"version-history":[{"count":4,"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/pages\/49\/revisions"}],"predecessor-version":[{"id":51,"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/pages\/49\/revisions\/51"}],"up":[{"embeddable":true,"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=\/wp\/v2\/pages\/2"}],"wp:attachment":[{"href":"http:\/\/sql.programisius.lt\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=49"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}