Demo parsing for iOS coredata multi-Table query (3) -- Query

Demo parsing for iOS coredata multi-Table query (2) -- insert Test Data

1. query Michael Zhang of the HR department

// Query the salary levels of Michael Jacob in the Development Department

Nslog (@ "---------- query the salary grade of Michael Jacob in the Development Department ----------");

Nslog (@ "---------- 1st Methods ----------");

// There are 1st Methods

Nsentitydescription * emety = [nsentitydescription entityforname: @ "employee" inmanagedobjectcontext: Self. managedobjectcontext];

Nsfetchrequest * frq = [[nsfetchrequest alloc] init];

[Frq setentity: emety];

Nspredicate * CDT = [nspredicate predicatewithformat: @ "em_name = % @", @ "James"];

[Frq setpredicate: CDT];

Nsarray * objs = [self. managedobjectcontext executefetchrequest: frq error: Nil];

Nspredicate * filter = [nspredicate predicatewithformat: @ "dept. dp_deptname = % @", @ "HR"];

Nsarray * ret = [objs filteredarrayusingpredicate: Filter];

Employee * r = (employee *) [RET lastobject];

Nslog (@ "% @", R. em_name );

Nslog (@ "% d", R. em_age );

Nslog (@ "% d", R. em_sex );

Nslog (@ "% @", R. em_bankcardid );

Nslog (@ "% @", R. Post. Salary. sy_level );

Nslog (@ "% F", R. Post. Salary. sy_scale );

Nslog (@ "% @", R. Bank. bk_name );

Nslog (@ "% @", R. Bank. bk_address );

// [Self. managedobjectcontext deleteobject: R];

// [Self savecontext];

Nslog (@ "---------- 2nd Methods ----------");

// There are 2nd Methods

Nsentitydescription * emety1 = [nsentitydescription entityforname: @ "department" inmanagedobjectcontext: Self. managedobjectcontext];

Nsfetchrequest * frq1 = [[nsfetchrequest alloc] init];

[Frq1 setentity: emety1];

Nspredicate * cdt1 = [nspredicate predicatewithformat: @ "dp_deptname = % @", @ "HR"];

[Frq1 setpredicate: cdt1];

Department * objs1 = [[self. managedobjectcontext executefetchrequest: frq1 error: Nil] lastobject];

Nsset * ret1 = objs1.employeeship;

Nspredicate * filter1 = [nspredicate predicatewithformat: @ "em_name = % @", @ "James"];

Employee * R1 = [[ret1 filteredsetusingpredicate: filter1] anyobject];

Nslog (@ "% @", r1.em _ name );

Nslog (@ "% d", r1.em _ age );

Nslog (@ "% d", r1.em _ sex );

Nslog (@ "% @", r1.em _ bankcardid );

Nslog (@ "% @", r1.post. Salary. sy_level );

Nslog (@ "% F", r1.post. Salary. sy_scale );

Nslog (@ "% @", r1.bank. bk_name );

Nslog (@ "% @", r1.bank. bk_address );

2. query O & M Department Ouyang

// Query the salary grade and account bank of the O & M Department named Ouyang

Nslog (@ "---------- query the salary grade of the O & M Department named Ouyang and the account opening bank ----------");

Nslog (@ "---------- 1st Methods ----------");

// There are 1st Methods

Nsentitydescription * entity = [nsentitydescription entityforname: @ "employee" inmanagedobjectcontext: Self. managedobjectcontext];

Nsfetchrequest * fetch = [[nsfetchrequest alloc] init];

[Fetch setentity: entity];

Nspredicate * qcmd = [nspredicate predicatewithformat: @ "em_name = % @", @ "Ouyang"];

[Fetch setpredicate: qcmd];

Nsarray * obs = [self. managedobjectcontext executefetchrequest: Fetch error: Nil];

Nspredicate * filter2 = [nspredicate predicatewithformat: @ "dept. dp_deptname = % @", @ "Dev"];

Nsarray * ret2 = [obs filteredarrayusingpredicate: filter2]; // filter data from the array.

Employee * r2 = [ret2 lastobject];

Nslog (@ "% @", r2.em _ name );

Nslog (@ "% d", r2.em _ age );

Nslog (@ "% d", r2.em _ sex );

Nslog (@ "% @", r2.em _ bankcardid );

Nslog (@ "% @", r2.post. Salary. sy_level );

Nslog (@ "% F", r2.post. Salary. sy_scale );

Nslog (@ "% @", r2.bank. bk_name );

Nslog (@ "% @", r2.bank. bk_address );

Nslog (@ "---------- 2nd Methods ----------");

// There are 2nd Methods

Nsentitydescription * emety3 = [nsentitydescription entityforname: @ "department" inmanagedobjectcontext: Self. managedobjectcontext];

Nsfetchrequest * frq3 = [[nsfetchrequest alloc] init];

[Frq3 setentity: emety3];

Nspredicate * cdt3 = [nspredicate predicatewithformat: @ "dp_deptname = % @", @ "Dev"];

[Frq3 setpredicate: cdt3];

Department * objs3 = [[self. managedobjectcontext executefetchrequest: frq3 error: Nil] lastobject];

Nsset * ret3 = objs3.employeeship;

Nspredicate * filter3 = [nspredicate predicatewithformat: @ "em_name = % @", @ "Ouyang"];

Employee * R3 = [[ret3 filteredsetusingpredicate: filter3] anyobject];

Nslog (@ "% @", r3.em _ name );

Nslog (@ "% d", r3.em _ age );

Nslog (@ "% d", r3.em _ sex );

Nslog (@ "% @", r3.em _ bankcardid );

Nslog (@ "% @", r3.post. Salary. sy_level );

Nslog (@ "% F", r3.post. Salary. sy_scale );

Nslog (@ "% @", r3.bank. bk_name );

Nslog (@ "% @", r3.bank. bk_address );

Multi-table queries mainly involve establishing correlation relationships between tables, and fully using the nspredicate query condition for filtering.